Photoelectric conversion device and photoelectric conversion device dye, and compound

ABSTRACT

The photoelectric conversion device described herein includes a working electrode having a dye-supported metal oxide electrode in which a dye is supported on a metal oxide layer. The dye includes a structure represented by general formula (I) 
                         
wherein A is a structure having a maximum absorption wavelength λmax of 350 to 500 nm in a methanol solution; B is a cyanine skeleton having a maximum absorption wavelength λmax of 500 to 700 nm in a methanol solution; Z 1  is any one divalent linking group selected from —CONR—, —NRCO—, —SO 2 NR—, and —NRSO 2 —; R in Z 1  is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an arylalkyl group having 7 to 20 carbon atoms; Y 1  and Y 2  are each independently an alkylene group having 1 to 8 carbon atoms, or a single bond, and may be the same or different; r is 1 or 2; m and n are each independently an integer of 0 to 2; and (m+n) is 1 or more.

TECHNICAL FIELD

The present invention relates to a photoelectric conversion device and aphotoelectric conversion device dye, and a compound.

BACKGROUND ART

Conventionally, dyes have been widely used in various technical fields.As one example, in the field of photoelectric conversion devices, forexample, a dye having photosensitization action is used in the workingelectrode of a dye-sensitized solar cell.

A dye-sensitized solar cell generally has an electrode having an oxidesemiconductor as a support for a dye. Such a dye absorbs incident lightand is excited, and this excited dye injects electrons into the supportto perform photoelectric conversion. In this type of dye-sensitizedsolar cell, high energy conversion efficiency can be theoreticallyexpected among organic solar cells. In addition, this type ofdye-sensitized solar cell can be produced at lower cost thanconventional solar cells using a silicon semiconductor, and therefore isconsidered to be very advantageous in terms of cost.

On the other hand, as dyes used in photoelectric conversion devices,organic dyes, such as ruthenium complex dyes and cyanine dyes, arewidely known. Particularly, cyanine dyes have relatively high stability,and can be easily synthesized, and therefore, various studies have beenmade.

For example, Patent Document 1 discloses a cyanine dye that has astructure in which an indolenine skeleton is bonded to both ends of amethine chain skeleton, and further has a carboxylic acid group as ananchor group to be adsorbed on an oxide semiconductor electrode.

In addition, Patent Document 2 discloses a composite dye in which aplurality of component dyes having different excitation levels from eachother are chemically bonded to each other, thereby forming a linear orbranched structure for electron transfer, the linear or branchedstructure is held at one end by an n-type semiconductor, the other endis a free end, and in the linear or branched structure, the plurality ofcomponent dyes are arranged in the order in which the excitation leveldecreases from the end of the linear or branched structure held by theabove n-type semiconductor toward the above free end.

Further, Patent Document 3 discloses a sensitizing dye in which a dyehaving an absorption maximum at 400 to 700 nm is bonded to a dye havingan absorption maximum at 700 to 1500 nm by a divalent linking group.

CITATION LIST Patent Document

-   Patent Document 1: Japanese Patent Laid-Open No. 2008-166119-   Patent Document 2: Japanese Patent Laid-Open No. 2004-363096-   Patent Document 3: Japanese Patent Laid-Open No. 2010-135281

SUMMARY OF INVENTION Technical Problem

However, it cannot be said that conventional (uncombined) dyes, typifiedby the cyanine dye described in the above Patent Document 1, and thelike, have a sufficiently wide absorption wavelength region, and itcannot be said that photoelectric conversion devices using these exhibitsufficient energy conversion efficiency.

Therefore, the widening of the absorption wavelength region has beenstudied, and for example, attempts to combine a plurality of dyes, as inthe technique described in the above Patent Document 2, have been made.But, the combined dye described in the above Patent Document 2sensitizes by two-photon excitation, and therefore, in a photoelectricconversion device using this, the current decreases to half, and highenergy conversion efficiency is not obtained.

On the other hand, the combined dye described in the above PatentDocument 3 has an absorption maximum at 700 to 1500 nm, and therefore,the LUMO of the dye is low, and it is difficult for the dye to exceedthe conductor of a metal oxide. Therefore, electrons cannot beefficiently injected from the dye into a metal oxide semiconductor.Therefore, in a photoelectric conversion device using the combined dyedescribed in the above Patent Document 3, high energy conversionefficiency is not obtained.

The present invention has been made in view of such circumstances, andit is an object of the present invention to provide a photoelectricconversion device that has excellent energy conversion efficiency andhigh durability, and a new dye that can implement such a photoelectricconversion device, and a compound that can be used as a precursor(intermediate) of such a new dye.

Solution to Problem

The present inventors have diligently studied over and over and, as aresult, found that the above problems are solved by using a dye having aspecific structure newly synthesized by the present inventors, leadingto the completion of the present invention.

Specifically, the present invention provides the following <1> to <11>.

<1>

A photoelectric conversion device comprising a working electrode havinga dye-supported metal oxide electrode in which a dye is supported on ametal oxide layer, wherein

the dye has a structure represented by the following general formula(I):

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; B is a cyanine skeleton having amaximum absorption wavelength λmax of 500 to 700 nm in a methanolsolution; Z¹ is any one divalent linking group selected from —CONR—,—NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is a hydrogen atom, an alkyl grouphaving 1 to 8 carbon atoms, or an arylalkyl group having 7 to 20 carbonatoms; Y¹ and Y² are each independently an alkylene group having 1 to 8carbon atoms, or a single bond, and may be the same or different; r is 1or 2; m and n are each independently an integer of 0 to 2; and (m+n) is1 or more.<2>

The photoelectric conversion device according to <1>, wherein the dyehas a structure represented by the following general formula (II):

wherein X¹ and X² are each independently an oxygen atom, a sulfur atom,a selenium atom, CR³R⁴, or NR⁵, and may be the same or different; R¹ toR⁵ are each independently a hydrogen atom, an alkyl group having 1 to 20carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkynylgroup having 2 to 8 carbon atoms, and may be the same or different,where R¹ to R⁵ may each be independently substituted by a halogen atom,a nitro group, a cyano group, an amino group, a hydroxyl group, an ethergroup, a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group, and R³ and R⁴ may be linked to form an alicyclicgroup having a 3- to 6-membered ring; R⁶ to R⁸ are each independently ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl grouphaving 6 to 12 carbon atoms, a halogen atom, or a cyano group, and maybe the same or different; R⁹ to R¹⁶ are each independently a hydrogenatom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or anaryl group having 6 to 12 carbon atoms, and may be the same ordifferent; in R⁹ to R¹⁶, R⁹ and R¹¹ may be eliminated or R¹³ and R¹⁵ maybe eliminated to each form an unsaturated bond, or R¹⁰ and R¹² may belinked or R¹⁴ and R¹⁶ may be linked to each form a benzene ring whichmay have a substituent, a naphthalene ring which may have a substituent,or a phenanthrene ring which may have a substituent; p is 1 or 2; Z¹ inthe formula replaces R¹ to R¹⁶ or a hydrogen atom contained in R¹ toR¹⁶; a substituent —Y²—COOH in the formula replaces R¹ to R¹⁶ or ahydrogen atom contained in R¹ to R¹⁶; An^(b−) is a b-valent anion; a is1 or 2, and is a coefficient for keeping a charge of the entire dyeneutral; b is 1 or 2; and m, n, r, Z¹, A, Y¹, and Y² are the same asdescribed in general formula (I).<3>

The photoelectric conversion device according to <2>, wherein the dyehas a structure represented by the following general formula (III):

wherein D¹ and D² are each independently a benzene ring which may have asubstituent, a naphthalene ring which may have a substituent, or aphenanthrene ring which may have a substituent, and may be the same ordifferent; and two substituents —Y²—COOH in the formula each replace R¹to R⁸ or a hydrogen atom contained in R¹ to R⁸, or substitute thebenzene ring, the naphthalene ring, or the phenanthrene ring representedby D¹ and D².<4>

The photoelectric conversion device according to any one of items <1> to<3>, wherein the A is one selected from the group consisting of thefollowing formulas (IV) to (VII):

wherein S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; q is 0 or 1; and the substituent —Y¹—COOH substitutes S¹;

wherein S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; R²⁴ is a hydrogen atom, an alkyl group having 1 to 20 carbonatoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl grouphaving 7 to 30 carbon atoms, or an anchor group; u is 0 or 1; and thesubstituent —Y¹—COOH substitutes S² and/or S³:

wherein R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group, andmay be the same or different; R²⁷ is a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms,an arylalkyl group having 7 to 30 carbon atoms, or an anchor group; R²⁸to R³¹ are each independently a hydrogen atom, a halogen atom, an alkylgroup having 1 to 20 carbon atoms, or an aryl group having 6 to 12carbon atoms, and may be the same or different, where R²⁸ and R³⁰ mayeach be eliminated to form an unsaturated bond, or R²⁹ and R³¹ may belinked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms, and may be the same or different; and R³⁴ to R⁴¹ are eachindependently a hydrogen atom, a halogen atom, a hydroxyl group, a cyanogroup, a nitro group, an alkyl group having 1 to 20 carbon atoms, anaryl group having 6 to 30 carbon atoms, or an arylalkyl group having 7to 30 carbon atoms, and may be the same or different.<5>

A photoelectric conversion device dye having a structure represented bythe following general formula (I):

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; B is a cyanine skeleton having amaximum absorption wavelength λmax of 500 to 700 nm in a methanolsolution; Z¹ is any one divalent linking group selected from —CONR—,—NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is a hydrogen atom, an alkyl grouphaving 1 to 8 carbon atoms, or an arylalkyl group having 7 to 20 carbonatoms; Y¹ and Y² are each independently an alkylene group having 1 to 8carbon atoms, or a single bond, and may be the same or different; r is 1or 2; m and n are each independently an integer of 0 to 2; and (m+n) is1 or more.<6>

The photoelectric conversion device dye according to <5>, having astructure represented by the following general formula (II):

wherein X¹ and X² are each independently an oxygen atom, a sulfur atom,a selenium atom, CR³R⁴, or NR⁵, and may be the same or different; R¹ toR⁵ are each independently a hydrogen atom, an alkyl group having 1 to 20carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkynylgroup having 2 to 8 carbon atoms, and may be the same or different,where R¹ to R⁵ may each be independently substituted by a halogen atom,a nitro group, a cyano group, an amino group, a hydroxyl group, an ethergroup, a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group, and R³ and R⁴ may be linked to form an alicyclicgroup having a 3- to 6-membered ring; R⁶ to R⁸ are each independently ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl grouphaving 6 to 12 carbon atoms, a halogen atom, or a cyano group, and maybe the same or different; R⁹ to R¹⁶ are each independently a hydrogenatom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or anaryl group having 6 to 12 carbon atoms, and may be the same ordifferent; in R⁹ to R¹⁶, R⁹ and R¹¹ may be eliminated or R¹³ and R¹⁵ maybe eliminated to each form an unsaturated bond, or R¹⁰ and R¹² may belinked or R¹⁴ and R¹⁶ may be linked to each form a benzene ring whichmay have a substituent, a naphthalene ring which may have a substituent,or a phenanthrene ring which may have a substituent; p is 1 or 2; Z¹ inthe formula replaces R¹ to R¹⁶ or a hydrogen atom contained in R¹ toR¹⁶; a substituent —Y²—COOH in the formula replaces R¹ to R¹⁶ or ahydrogen atom contained in R¹ to R¹⁶; An^(b−) is a b-valent anion; a is1 or 2, and is a coefficient for keeping a charge of the entire dyeneutral; b is 1 or 2; and m, n, r, Z¹, A, Y¹, and Y² are the same asdescribed in general formula (I).<7>

The photoelectric conversion device dye according to <6>, having astructure represented by the following general formula (III):

wherein D¹ and D² are each independently a benzene ring which may have asubstituent, a naphthalene ring which may have a substituent, or aphenanthrene ring which may have a substituent, and may be the same ordifferent; and two substituents —Y²—COOH in the formula each replace R¹to R⁸ or a hydrogen atom contained in R¹ to R⁸, or substitute thebenzene ring, the naphthalene ring, or the phenanthrene ring representedby D¹ and D².

<8>

The photoelectric conversion device dye according to any one of items<5> to <7>, wherein the A is one selected from the group consisting ofthe following formulas (IV) to (VII):

wherein S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; q is 0 or 1; and the substituent —Y¹—COOH substitutes S¹;

wherein S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; R²⁴ is a hydrogen atom, an alkyl group having 1 to 20 carbonatoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl grouphaving 7 to 30 carbon atoms, or an anchor group, u is 0 or 1; and thesubstituent —Y¹—COOH substitutes S² and/or S³:

wherein R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group, andmay be the same or different, R²⁷ is a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms,an arylalkyl group having 7 to 30 carbon atoms, or an anchor group; R²⁸to R³¹ are each independently a hydrogen atom, a halogen atom, an alkylgroup having 1 to 20 carbon atoms, or an aryl group having 6 to 12carbon atoms, and may be the same or different, where R²⁸ and R³⁰ mayeach be eliminated to form an unsaturated bond, or R²⁹ and R³¹ may belinked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms, and may be the same or different; and R³⁴ to R⁴¹ are eachindependently a hydrogen atom, a halogen atom, a hydroxyl group, a cyanogroup, a nitro group, an alkyl group having 1 to 20 carbon atoms, anaryl group having 6 to 30 carbon atoms, or an arylalkyl group having 7to 30 carbon atoms, and may be the same or different.<9>

A compound having a structure represented by the following formula (IX):

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution, Z¹ is any one divalent linkinggroup selected from —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or anarylalkyl group having 7 to 20 carbon atoms; D¹ is a benzene ring whichmay have a substituent, a naphthalene ring which may have a substituent,or a phenanthrene ring which may have a substituent; R¹ is a hydrogenatom, an alkyl group having 1 to 20 carbon atoms, an alkenyl grouphaving 2 to 8 carbon atoms, or an alkynyl group having 2 to 8 carbonatoms, each of which may be substituted by a halogen atom, a nitrogroup, a cyano group, an amino group, a hydroxyl group, an ether group,a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group; R⁴² are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; X¹ is an oxygen atom, a sulfur atom, a selenium atom, CR³R⁴,or NR⁵; R³ to R⁵ are each independently a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an alkenyl group having 2 to 8 carbonatoms, or an alkynyl group having 2 to 8 carbon atoms, and may be thesame or different; R³ to R⁵ may each be independently substituted by ahalogen atom, a nitro group, a cyano group, an amino group, a hydroxylgroup, an ether group, a carbonyl group, an aromatic ring, aheterocyclic ring, or a metallocenyl group, and R³ and R⁴ may be linkedto form an alicyclic group having a 3- to 6-membered ring; Y¹ is analkylene group having 1 to 8 carbon atoms, or a single bond; m is 0 to2; An^(b−) is a b-valent anion; a is 1 or 2, and is a coefficient forkeeping a charge of the entire dye neutral; and b is 1 or 2.

The compound having the structure represented by the above formula (IX)is equivalent to a compound having a structure represented by thefollowing formula (IX)′ in terms of synthesis.

wherein A, Z¹, D¹, R¹, R⁴², X¹, Y¹, and m are the same as described inthe above formula (IX).<10>

The compound according to <9>, having a structure represented by thefollowing formula (X):

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; Z² is any one divalent linkinggroup selected from —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—, R in Z² is ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or anarylalkyl group having 7 to 20 carbon atoms; D¹ is a benzene ring whichmay have a substituent, a naphthalene ring which may have a substituent,or a phenanthrene ring which may have a substituent; R¹ is a hydrogenatom, an alkyl group having 1 to 20 carbon atoms, an alkenyl grouphaving 2 to 8 carbon atoms, or an alkynyl group having 2 to 8 carbonatoms, each of which may be substituted by a halogen atom, a nitrogroup, a cyano group, an amino group, a hydroxyl group, an ether group,a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group, X¹ is an oxygen atom, a sulfur atom, a seleniumatom, CR³R⁴, or NR⁵; R³ to R⁵ are each independently a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 8carbon atoms, or an alkynyl group having 2 to 8 carbon atoms, and may bethe same or different, where R³ to R⁵ may each be independentlysubstituted by a halogen atom, a nitro group, a cyano group, an aminogroup, a hydroxyl group, an ether group, a carbonyl group, an aromaticring, a heterocyclic ring, or a metallocenyl group, and R³ and R⁴ may belinked to form an alicyclic group having a 3- to 6-membered ring;An^(b−) is a b-valent anion; a is 1 or 2, and is a coefficient forkeeping the charge of the entire dye neutral; and b is 1 or 2.<11>

The compound according to item <9> or <10>, wherein the A is oneselected from the group consisting of the following formulas (IV) to(VII):

wherein S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; q is 0 or 1, and the substituent —Y¹—COOH substitutes S¹;

wherein S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; R²⁴ is a hydrogen atom, an alkyl group having 1 to 20 carbonatoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl grouphaving 7 to 30 carbon atoms, or an anchor group; u is 0 or 1; and thesubstituent —Y¹—COOH substitutes S² and/or S³:

wherein R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group, andmay be the same or different; R²⁷ is a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms,an arylalkyl group having 7 to 30 carbon atoms, or an anchor group; R²⁸to R³¹ are each independently a hydrogen atom, a halogen atom, an alkylgroup having 1 to 20 carbon atoms, or an aryl group having 6 to 12carbon atoms, and may be the same or different, where R²⁸ and R³⁰ mayeach be eliminated to form an unsaturated bond, or R²⁹ and R³¹ may belinked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms, and may be the same or different; and R³⁴ to R⁴¹ are eachindependently a hydrogen atom, a halogen atom, a hydroxyl group, a cyanogroup, a nitro group, an alkyl group having 1 to 20 carbon atoms, anaryl group having 6 to 30 carbon atoms, or an arylalkyl group having 7to 30 carbon atoms, and may be the same or different.

Advantageous Effects of Invention

According to the present invention, a photoelectric conversion devicedye that has a wide absorption wavelength region, and has not onlyexcellent adsorption properties (adhesiveness) on a metal oxide layerbut also excellent energy transfer efficiency is implemented. Therefore,by using this photoelectric conversion device dye, a photoelectricconversion device that has enhanced photoelectric conversioncharacteristics and durability can be easily and reliably implemented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram showing the presumed mechanism of theexcitation and sensitization action of a dye in this embodiment.

FIG. 2 is a cross-sectional view showing the schematic configuration ofa dye-sensitized solar cell 100.

FIG. 3 shows the ultraviolet-visible absorption spectrum of a dye 5.

FIG. 4 shows the ultraviolet-visible absorption spectrum of dye (C3).

FIG. 5 shows the ultraviolet-visible absorption spectrum of dye (C4).

FIG. 6 shows the ultraviolet-visible absorption spectrum of a mixture ofdye (C3) and dye (C4).

DESCRIPTION OF EMBODIMENT

An embodiment of the present invention will be described below. Likenumerals refer to like elements, and redundant description is omitted.In addition, positional relationships, such as top, bottom, left, andright, are based on the positional relationships shown in the drawingsunless otherwise specified. Further, the dimensional ratios in thedrawings are not limited to the ratios shown. In addition, the followingembodiment is illustration for explaining the present invention, and thepresent invention is not limited only to the embodiment.

A dye in this embodiment can be preferably used for a photoelectricconversion device, such as a dye-sensitized solar cell, and is acompound having a structure represented by general formula (I). Thecompound having the structure represented by general formula (1) hasadsorption properties (bonding properties) on a metal oxide layer(support) comprising a metal oxide semiconductor material, and absorbslight, is excited, and injects electrons into the support.

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; B is a cyanine skeleton having amaximum absorption wavelength λmax of 500 to 700 nm in a methanolsolution; Z¹ is any one divalent linking group selected from —CONR—,—NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is a hydrogen atom, an alkyl grouphaving 1 to 8 carbon atoms, or an arylalkyl group having 7 to 20 carbonatoms; Y¹ and Y² are each independently an alkylene group having 1 to 8carbon atoms, or a single bond, and may be the same or different; r is 1or 2; m and n are each independently an integer of 0 to 2; and (m+n) is1 or more.

In general formula (I), the structure having a maximum absorptionwavelength λmax of 350 to 500 nm in a methanol solution, which is A, isnot particularly limited, and examples thereof include a structure inwhich m+1 hydrogen atoms or monovalent substituents are abstracted froma yellow dye having a maximum absorption wavelength λmax of 350 to 500nm. Examples of such a yellow dye include, but are not particularlylimited to, fluorescein, rhodamine, cyanine, merocyanine, hemicyanine,azo, polycyclic quinone, indigo, diphenylmethane, benzophenone, pyrene,perylene, semisquarylium, metal-free porphyrin, and metal porphyrin.

In general formula (I), the cyanine skeleton having a maximum absorptionwavelength λmax of 500 to 700 nm in a methanol solution, which is B, isnot particularly limited, and examples thereof include a structure inwhich n+r+1 hydrogen atoms or monovalent substituents are abstractedfrom a cyanine dye having a maximum absorption wavelength λmax of 500 to700 nm in a methanol solution.

In general formula (I), the alkyl group having 1 to 8 carbon atoms isnot particularly limited, and may be any of linear, branched, or cyclic.Specific examples thereof include methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl, s-butyl, t-butyl, pentyl, isopentyl, neopentyl,n-hexyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl,cyclohexyl, cyclopentyl, cyclohexylmethyl, n-heptyl, and n-octyl.

In general formula (I), the arylalkyl group having 7 to 20 carbon atomsis not particularly limited, and may be any of linear, branched, orcyclic. Specific examples thereof include benzyl, phenylethyl,phenylpropyl, p-methylbenzyl, and naphthylmethyl.

In general formula (I), the alkylene group having 1 to 8 carbon atoms isnot particularly limited, and may be any of linear, branched, or cyclic.Specific examples thereof include methylene, ethylene, propylene,butylene, pentylene, and hexylene.

The detailed mechanism of action for the fact that the dye in thisembodiment has a wide absorption wavelength region, and has not onlyexcellent adsorption properties (adhesiveness) on a metal oxide layerbut also excellent energy transfer efficiency is uncertain, but ispresumed as follows.

In the dye in this embodiment, the structure having a maximum absorptionwavelength λmax of 350 to 500 nm in a methanol solution (second lightabsorption site) and the cyanine skeleton having a maximum absorptionwavelength λmax of 500 to 700 nm in a methanol solution (first lightabsorption site) are linked by the linking group Z¹, and thus, theabsorption wavelength region is widened. Moreover, an amide bond or asulfonamide bond is used as the linking group, and therefore, energytransfer from the second light absorption site B to the first lightabsorption site A is efficiently performed. For example, it has becomeclear from the findings of the present inventors that in the comparisonof a dye of the following formula (A) and a dye of the following formula(B), the fluorescence quantum yield of cyanine when the second lightabsorption site is excited is higher in the dye of the following formula(A) (5.1% in the dye of the following formula (A), and 0.1% in the dyeof the following formula (B)).

Moreover, it has been confirmed that in the dye in this embodiment,light emission from the first light absorption site A is observed withhigh efficiency even if the second light absorption site B is excited.This suggests that even if the second light absorption site B is amaterial with low injection into a metal oxide, light energy absorbed bythe first light absorption site and light energy absorbed by the secondlight absorption site are both transferred to a metal oxidesemiconductor with high efficiency when a material with high electroninjection into a metal oxide is selected for the first light absorptionsite A.

Conventionally, in order to widen the absorption wavelength region,using two or more (uncombined) dyes having different absorptionwavelength regions, in combination, has also been studied. However, evenif two or more (uncombined) dyes are used in combination, it isdifficult to adsorb the dyes on a metal oxide surface in an intendedadsorption proportion (sufficiently adsorb a dye having poor adsorptionproperties on a metal oxide surface) because the adsorption propertiesof the dyes on the metal oxide surface are different. Therefore, it isdifficult to widen the absorption wavelength region. In addition, it isconsidered that the sites of a metal oxide surface on which dyes can beadsorbed are limited. Therefore, even if an attempt is made to mix twoor more (uncombined) dyes and adsorb the mixed dyes on a metal oxidesurface, these are adsorbed sharing the limited sites, and therefore,the amount of the adsorbed dyes per unit area cannot be increased. Onthe other hand, in the case of a (combined) dye linked by the linkinggroup Z¹, like the dye in this embodiment, the (combined) dye is asingle dye, and therefore, it is not necessary to share the adsorptionsites with other dyes as described above. In addition, although the(combined) dye is a single dye, two dye structures are included, andtherefore, the amount of the adsorbed dye (dye structures) per unit areacan be increased. Further, —Y¹—COOH or —Y²—COOH, which is an anchorgroup, is protected by the bulkiness of the linking group Z¹ and thefirst light absorption site A, and therefore, high resistance in apeeling test can be shown.

Furthermore, in the dye in this embodiment, —Y¹—COOH or —Y²—COOH isintroduced as an anchor group, and therefore, the adsorption properties(adhesiveness) on a metal oxide surface are enhanced. Thus, not onlyelectron transfer from the dye to a metal oxide semiconductor ispromoted, but also the amount of the dye adsorbed on a metal oxidesurface is enhanced. It is considered that as a result of these actionsin combination, in a photoelectric conversion device using the dye inthis embodiment, the proportion of the amount of electrons injected fromthe dye in this embodiment into a metal oxide semiconductor is high withrespect to the amount of emitted light, and IPCE (Incident Photons toCurrent conversion Efficiency) is improved, and as a result, conversionefficiency is improved, and durability is enhanced. However, the actionsare not limited to these. IPCE represents the conversion proportion ofthe number of electrons of photocurrent to the number of photons ofemitted light in a photoelectric conversion device, and is obtained byIPCE (%)=Isc×1240/λ×1/φ wherein Isc is short circuit current, λ iswavelength, and φ is incident light intensity.

The structure represented by the above general formula (I) is preferablya structure represented by the following general formula (II):

wherein X¹ and X² are each independently an oxygen atom, a sulfur atom,a selenium atom, CR³R⁴, or NR⁵, and may be the same or different; R¹ toR⁵ are each independently a hydrogen atom, an alkyl group having 1 to 20carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkynylgroup having 2 to 8 carbon atoms, and may be the same or different,where R¹ to R⁵ may each be independently substituted by a halogen atom(F, Cl, Br, or the like), a nitro group, a cyano group, an amino group,a hydroxyl group, an ether group, a carbonyl group, an aromatic ring, aheterocyclic ring, or a metallocenyl group, and R³ and R⁴ may be linkedto form an alicyclic group having a 3- to 6-membered ring; R⁶ to R⁸ areeach independently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, an aryl group having 6 to 12 carbon atoms, a halogen atom (F, Cl,Br, or the like), or a cyano group, and may be the same or different; R⁹to R¹⁶ are each independently a hydrogen atom, a halogen atom (F, Cl,Br, or the like), an alkyl group having 1 to 20 carbon atoms, or an arylgroup having 6 to 12 carbon atoms, and may be the same or different; inR⁹ to R¹⁶, R⁹ and R¹¹ may be eliminated or R¹³ and R¹⁵ may be eliminatedto each form an unsaturated bond, or R¹⁰ and R¹² may be linked or R¹⁴and R¹⁶ may be linked to each form a benzene ring which may have asubstituent, a naphthalene ring which may have a substituent, or aphenanthrene ring which may have a substituent; p is 1 or 2; Z¹ in theformula replaces R¹ to R¹⁶ or a hydrogen atom contained in R¹ to R¹⁶; asubstituent —Y²—COOH in the formula replaces R¹ to R¹⁶ or a hydrogenatom contained in R¹ to R¹⁶; An^(b−) is a b-valent anion; a is 1 or 2,and is a coefficient for keeping the charge of the entire dye neutral; bis 1 or 2; and m, n, r, Z¹, A, Y¹, and Y² are the same as described ingeneral formula (I).

In general formula (II), the alkyl group having 1 to 20 carbon atoms isnot particularly limited, and may be any of linear, branched, or cyclic.Specific examples thereof include methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl, s-butyl, t-butyl, pentyl, isopentyl, neopentyl,n-hexyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl,cyclohexyl, cyclopentyl, cyclohexylmethyl, n-heptyl, n-octyl, n-decyl,n-hexadecyl, and n-dodecyl.

In general formula (II), the alkenyl group having 2 to 8 carbon atoms isnot particularly limited, and examples thereof include a vinyl group, anallyl group, a butenyl group, a hexenyl group, and a decenyl group.

In general formula (II), the alkynyl group having 2 to 8 carbon atoms isnot particularly limited, and examples thereof include an ethynyl groupand a propynyl group.

In general formula (II), the aromatic ring and the heterocyclic ring arenot particularly limited, and examples thereof include benzene,naphthalene, anthracene, phenanthrene, pyrrole, furan, thiophene,imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole,benzofuran, benzothiophene, benzimidazole, benzoxazole, benzothiazole,indole, indolenine, fluorene, carbazole, pyridine, pyridazine,pyrimidine, pyrazine, piperidine, piperazine, morpholine, 2H-pyran, and4H-pyran. Examples of the substituent of the aromatic ring and theheterocyclic ring include, but are not particularly limited to, ahydroxyl group, a carboxyl group, a nitro group, a cyano group, halogenatoms (F, Cl, Br, and the like), the alkyl groups having 1 to 8 carbonatoms described above, the arylalkyl groups having 7 to 30 carbon atomsdescribed above, the amino groups described above, alkyl halide groupshaving 1 to 4 or less carbon atoms (for example, CF₃ and CCl₃), andalkoxy groups having 1 to 4 carbon atoms (for example, methoxy, ethoxy,propyloxy, isopropyloxy, butyloxy, sec-butyloxy, and tert-butyloxy).

In general formula (II), examples of the alicyclic group when R³ and R⁴are linked to form an alicyclic group having a 3- to 6-membered ringinclude cyclopropane, cyclobutane, cyclopentane, and cyclohexane.

In general formula (II), the alkyl group having 1 to 8 carbon atoms isnot particularly limited, and may be any of linear, branched, or cyclic.Specific examples thereof include methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl, s-butyl, t-butyl, pentyl, isopentyl, neopentyl,n-hexyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl,cyclohexyl, cyclopentyl, cyclohexylmethyl, n-heptyl, and n-octyl.

In general formula (II), the aryl group having 6 to 12 carbon atoms isnot particularly limited, and specific examples thereof include a phenylgroup, a naphthyl group, an azulenyl group, a phenanthrene group, and abiphenyl group.

In general formula (II), the anion of An^(b−) is a counteranion forkeeping the charge of the entire dye neutral, and any can be used aslong as it is a monovalent or divalent anion. In An^(b−) in generalformula (II), specific examples of the anion in the case of b=1(monovalent anion; An⁻) are not particularly limited, and include ahalide ion, such as a fluoride ion (F⁻), a chloride ion (Cl⁻), a bromideion (Br⁻), or an iodide ion (I⁻), an inorganic anion, such as ahexafluorophosphate ion (PF₆ ⁻), a hexafluoroantimonate ion (SbF₆ ⁻), aperchlorate ion (ClO₄ ⁻), a tetrafluoroborate ion (BF₄ ⁻), a chlorateion, or a thiocyanate ion, an organic sulfonate anion, such as abenzenesulfonate ion, a toluenesulfonate ion, atrifluoromethanesulfonate ion, a diphenylamine-4-sulfonate ion, a2-amino-4-methyl-5-chlorobenzenesulfonate ion, a2-amino-5-nitrobenzenesulfonate ion, a N-alkyldiphenylamine-4-sulfonateion, or a N-aryldiphenylamine-4-sulfonate ion, and an organic phosphateanion, such as an octyl phosphate ion, a dodecyl phosphate ion, anoctadecyl phosphate ion, a phenyl phosphate ion, a nonylphenyl phosphateion, or a 2,2′-methylenebis(4,6-di-t-butylphenyl)phosphonate ion, and inaddition, a bistrifluoromethylsulfonylimide ion, abisperfluorobutanesulfonylimide ion, aperfluoro-4-ethylcyclohexanesulfonate ion, atetrakis(pentafluorophenyl)borate ion, and a tris(fluoroalkylsulfonyl)carbanion. In addition, in An^(b−) in general formula (II), the anion inthe case of b=2 (divalent anion; An²⁻) is not particularly limited, andexamples thereof include a sulfate ion (SO₄ ²⁻), a benzenedisulfonateion, and a naphthalenedisulfonate ion. In addition, the dye in thisembodiment may be the so-called inner salt in which a salt is formed ina molecule. In this case, in the dye in this embodiment, for example, anacidic group, such as a —CH₂CH₂COOH group, introduced into the nitrogenatom of an indolenine skeleton is ionized.

The structure represented by the above general formula (II) ispreferably a structure represented by the following general formula(III):

wherein D¹ and D² are each independently a benzene ring which may have asubstituent, a naphthalene ring which may have a substituent, or aphenanthrene ring which may have a substituent, and may be the same ordifferent; and two substituents —Y²—COOH in the formula each replace R¹to R⁸ or a hydrogen atom contained in R¹ to R⁸, or substitute thebenzene ring, the naphthalene ring, or the phenanthrene ring representedby D¹ and D².

In the structures represented by the above general formulas (I) to(III), A, which is the structure having a maximum absorption wavelengthλmax of 350 to 500 nm in a methanol solution, is preferably any one ofthe following formulas (IV) to (VII):

wherein S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom (F, Cl, Br, or the like), or a cyano group, andmay be the same or different; q is 0 or 1; and the above substituent—Y¹—COOH substitutes S¹;

wherein S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; R²⁴ is a hydrogen atom, an alkyl group having 1 to 20 carbonatoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl grouphaving 7 to 30 carbon atoms, or an anchor group; u is 0 or 1; and theabove substituent —Y¹—COOH substitutes S² and/or S³:

wherein R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group, andmay be the same or different; R²⁷ is a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms,an arylalkyl group having 7 to 30 carbon atoms, or an anchor group; R²⁸to R³¹ are each independently a hydrogen atom, a halogen atom, an alkylgroup having 1 to 20 carbon atoms, or an aryl group having 6 to 12carbon atoms, and may be the same or different, where R²⁸ and R³⁰ mayeach be eliminated to form an unsaturated bond, or R²⁹ and R³¹ may belinked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the above substituent—Y¹—COOH substitutes S³; and

wherein R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms, and may be the same or different; and R³⁴ to R⁴¹ are eachindependently a hydrogen atom, a halogen atom, a hydroxyl group, a cyanogroup, a nitro group, an alkyl group having 1 to 20 carbon atoms, anaryl group having 6 to 30 carbon atoms, or an arylalkyl group having 7to 30 carbon atoms, and may be the same or different.

In the above formulas (IV) to (VII), specific examples of the aromaticring and the heterocyclic ring, the substituent of the aromatic ring andthe heterocyclic ring, the alkyl group having 1 to 8 carbon atoms, thehalogen atom, the alkyl group having 1 to 20 carbon atoms, the arylgroup having 6 to 30 carbon atoms, and the arylalkyl group having 7 to30 carbon atoms include, but are not particularly limited to, thosedescribed in the above general formulas (I) and (II). In addition, inthe above formulas (IV) to (VII), the anchor group means a substituentthat has chemical or electrostatic affinity or bonding ability to ametal oxide layer (support) comprising a metal oxide, and specifically,specific examples thereof include a carboxylic acid group, a sulfonicacid group, and a phosphoric acid group.

In the above general formulas (I) to (III), Z¹ is not particularlylimited as long as it is any one of —CONR—, —NRCO—, —SO₂NR—, and—NRSO₂—. In terms of further enhancing energy conversion efficiency, Z¹is preferably —CONR— or —NRCO—. In addition, in the above generalformulas (I) to (II), it is preferable that m is 0 and n is 2, in termsof further enhancing energy conversion efficiency and durability. Whenthe anchor group (substituent —Y²—COOH) is formed only on the cyanineskeleton side in this manner, the dye is adsorbed with the cyanineskeleton side oriented to a metal oxide layer surface. Therefore, energytransfer from the second light absorption site to the first lightabsorption site is efficiently performed, and as a result, light energyabsorbed by the first light absorption site and light energy absorbed bythe second light absorption site are both transferred to the metal oxidesemiconductor with high efficiency. In addition, the adsorption state ofthe dye is relatively bulky, and further, the anchor group (substituent—Y²—COOH) adsorbed on the metal oxide layer is relativelyhydrophobically protected by the steric hindrance of the dye itself.Therefore, the peeling properties of the dye with respect to water areenhanced, and as a result, the durability is further enhanced.

The linking sites of the above Z¹ to the above A and B are notparticularly limited. Specific examples of preferable linking structuresof A and Z¹, and preferable linking structures of B and Z¹ areillustrated below.

In this embodiment, a further preferable dye has a structure representedby the following general formula (VIII), and a particularly preferabledye has a structure represented by the following general formula (IX).

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; Z¹ is any one divalent linkinggroup selected from —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or anarylalkyl group having 7 to 20 carbon atoms; X¹ and X² are eachindependently an oxygen atom, a sulfur atom, a selenium atom, CR³R⁴, orNR⁵, and may be the same or different; D² is a benzene ring which mayhave a substituent, a naphthalene ring which may have a substituent, ora phenanthrene ring which may have a substituent; R¹ to R² are eachindependently —Y²—COOH, a hydrogen atom, an alkyl group having 1 to 20carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkynylgroup having 2 to 8 carbon atoms, where at least one of R¹ to R² is—Y²—COOH, and Y² is each independently an alkylene group having 1 to 8carbon atoms, or a single bond; R³ to R⁵ are each independently ahydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenylgroup having 2 to 8 carbon atoms, or an alkynyl group having 2 to 8carbon atoms, and may be the same or different; R⁶ to R⁸ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, an aryl group having 6 to 12 carbon atoms, a halogen atom, or acyano group, and may be the same or different; p is 1 or 2; An^(b−) is ab-valent anion; a is 1 or 2, and is a coefficient for keeping the chargeof the entire dye neutral; and b is 1 or 2.

wherein symbols are similar to those described in the above generalformula (VIII).

In the dye having the structure represented by the above general formula(VIII), the structure having a maximum absorption wavelength λmax of 350to 500 nm in a methanol solution (second light absorption site) and thecyanine skeleton (first light absorption site) are linked by the linkinggroup with high efficiency energy transfer, and in the dye having thestructure represented by the above general formula (IX), they are linkedby a particularly excellent amide bond. Moreover, the anchor group(substituent —Y²—COOH) is formed only on the cyanine skeleton side.Therefore, the energy conversion efficiency and the durability areparticularly excellent.

In the above general formula (VIII), specific examples of A, X¹, X², Y²,D², R¹ to R⁸, p, An^(b−), a, and b are similar to those described above.

Specific examples (1) to (57) of the dye in this embodiment are listedbelow, but are not particularly limited to these.

As long as the dye in this embodiment has the structure represented bythe above general formula (I), more preferably the structure representedby the above general formula (II) or (III), and further preferably thestructure represented by the above general formula (VIII), otherstructures are not particularly limited. In addition, as long as the dyein this embodiment has these structures, even in an enantiomer ordiastereoisomer thereof or a mixture thereof, similar effects areobtained.

The dye in this embodiment can be obtained by a method using a publiclyknown or well-known general reaction, and is not particularly limited.As a typical example of the synthesis method, the dye in this embodimentcan be synthesized by reacting an intermediate, such as a quaternaryammonium salt, with a bridging agent or the like, or hemicyanine or thelike by routes represented by the following reaction formulas (a) to(c).

The quaternary ammonium salt can be synthesized, for example, using anitrogen-containing heterocyclic compound and an electrophile, such asan alkyl halide. In addition, anion exchange may be performed asrequired.

Reaction Formula (a)

Reaction Formula (b)

A symmetrical trimethine dye and pentamethine dye can be synthesizedusing an intermediate, such as a quaternary ammonium salt, and agenerally known bridging agent. In addition, compounds other thanbridging agents are also widely known, and they are shown together.

Examples of Compounds Other than Bridging Agents

An asymmetrical trimethine and pentamethine dye can be synthesized, forexample, using a quaternary ammonium salt and hemicyanine.

Reaction Formula (c)

The intermediate, such as a quaternary ammonium salt, described above ispreferably a compound having a structure represented by the followingformula (IX), more preferably a compound having a structure representedby the following formula (X). In addition, for a reason similar to theabove, A in the structures represented by the following formula (IX) andthe following formula (X) is more preferably any of the above-describedformulas (IV) to (VII).

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; Z¹ is any one divalent linkinggroup selected from —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or anarylalkyl group having 7 to 20 carbon atoms; D¹ is a benzene ring whichmay have a substituent, a naphthalene ring which may have a substituent,or a phenanthrene ring which may have a substituent; R¹ is a hydrogenatom, an alkyl group having 1 to 20 carbon atoms, an alkenyl grouphaving 2 to 8 carbon atoms, or an alkynyl group having 2 to 8 carbonatoms, each of which may be substituted by a halogen atom, a nitrogroup, a cyano group, an amino group, a hydroxyl group, an ether group,a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group; R⁴² are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbonatoms, a halogen atom, or a cyano group, and may be the same ordifferent; X¹ is an oxygen atom, a sulfur atom, a selenium atom, CR³R⁴,or NR⁵; R³ to R⁵ are each independently a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an alkenyl group having 2 to 8 carbonatoms, or an alkynyl group having 2 to 8 carbon atoms, and may be thesame or different, where R³ to R⁵ may each be independently substitutedby a halogen atom, a nitro group, a cyano group, an amino group, ahydroxyl group, an ether group, a carbonyl group, an aromatic ring, aheterocyclic ring, or a metallocenyl group, and R³ and R⁴ may be linkedto form an alicyclic group having a 3- to 6-membered ring; Y¹ is analkylene group having 1 to 8 carbon atoms, or a single bond; m is 0 to2; An^(b−) is a b-valent anion; a is 1 or 2, and is a coefficient forkeeping the charge of the entire dye neutral; and b is 1 or 2.

wherein A is a structure having a maximum absorption wavelength λmax of350 to 500 nm in a methanol solution; Z² is any one divalent linkinggroup selected from —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—; R in Z² is ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or anarylalkyl group having 7 to 20 carbon atoms; D¹ is a benzene ring whichmay have a substituent, a naphthalene ring which may have a substituent,or a phenanthrene ring which may have a substituent; R¹ is a hydrogenatom, an alkyl group having 1 to 20 carbon atoms, an alkenyl grouphaving 2 to 8 carbon atoms, or an alkynyl group having 2 to 8 carbonatoms, each of which may be substituted by a halogen atom, a nitrogroup, a cyano group, an amino group, a hydroxyl group, an ether group,a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group; X¹ is an oxygen atom, a sulfur atom, a seleniumatom, CR³R⁴, or NR⁵; R³ to R⁵ are each independently a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 8carbon atoms, or an alkynyl group having 2 to 8 carbon atoms, and may bethe same or different, where R³ to R⁵ may each be independentlysubstituted by a halogen atom, a nitro group, a cyano group, an aminogroup, a hydroxyl group, an ether group, a carbonyl group, an aromaticring, a heterocyclic ring, or a metallocenyl group, and R³ and R⁴ may belinked to form an alicyclic group having a 3- to 6-membered ring;An^(b−) is a b-valent anion; a is 1 or 2, and is a coefficient forkeeping the charge of the entire dye neutral; and b is 1 or 2.

Specific examples (a-1) to (a-12) of the intermediate, such as aquaternary ammonium salt, which are included in the compounds having thestructures represented by the above formula (IX) and the above formula(X) are illustrated below.

Next, an example of the use of a photoelectric conversion device dye inthis embodiment will be described.

FIG. 2 is a cross-sectional view showing the schematic configuration ofa dye-sensitized solar cell 100, which is a photoelectric conversiondevice in this embodiment.

The dye-sensitized solar cell 100 in this embodiment comprises a workingelectrode 11, a counter electrode 21, and an electrolyte 31 providedbetween these working electrode 11 and counter electrode 21. At leastone of the working electrode 11 and the counter electrode 21 is anelectrode having light transmission properties. The working electrode 11and the counter electrode 21 are opposed to each other via a spacer 41,and the electrolyte 31 is enclosed in a sealing space defined by theseworking electrode 11, counter electrode 21, and spacer 41, and a sealingmember not shown.

The working electrode 11 functions as a negative electrode with respectto an external circuit. The working electrode 11 comprises a porousmetal oxide layer 13 (metal oxide semiconductor layer) containing ametal oxide (metal oxide semiconductor material) on the conductivesurface 12 a of a substrate 12, and the dye in this embodiment describedabove is supported (adsorbed) on the metal oxide layer 13, and thus, adye-supported metal oxide electrode 14 is formed. In other words, theworking electrode 11 in this embodiment has a configuration in which acomposite structure in which the dye in this embodiment described aboveis supported (adsorbed) on the metal oxide surface of the metal oxidelayer 13 is laminated on the conductive surface 12 a of the substrate 12(the dye-supported metal oxide electrode 14).

The type, dimensions, and shape of the substrate 12 are not particularlylimited as long as it can support at least the metal oxide layer 13. Forexample, a plate-shaped or sheet-shaped one can be preferably used.Specific examples thereof include a glass substrate, a plasticsubstrate, such as polyethylene, polypropylene, polystyrene, tetraacetylcellulose (TAC), polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide(PPS), polycarbonate (PC), polyarylate (PAR), polysulfone (PSF),polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, orbrominated phenoxy, a metal substrate or an alloy substrate, a ceramicsubstrate, or a laminate thereof. In addition, the substrate 12preferably has light transmission properties, and one having excellentlight transmission properties in the visible light region is morepreferable. Further, the substrate 12 preferably has flexibility. Inthis case, structures in various forms utilizing the flexibility can beprovided.

The conductive surface 12 a can be provided on the substrate 12, forexample, by forming a transparent conductive film on the substrate 12,like a conductive PET film. In addition, by using the substrate 12having conductivity, the treatment for providing the conductive surface12 a on the substrate 12 can be omitted. Specific examples of thetransparent conductive film include, but are not particularly limitedto, a metal thin film comprising gold (Au), silver (Ag), platinum (Pt),or the like, and one formed of a conductive polymer or the like, as wellas indium-tin oxide (ITO), indium-zinc oxide (IZO), SnO₂, and InO₃, aswell as FTO (F—SnO₂) in which SnO₂ is doped with fluorine. Each of thesemay be used alone, or a plurality of these may be used in combination.The method for forming the transparent conductive film is notparticularly limited, and a publicly known method, for example, vapordeposition, CVD, spraying, spin coating, or immersion, can be applied.In addition, the film thickness of the transparent conductive film canbe appropriately set. The conductive surface 12 a of the substrate 12may be subjected to appropriate surface modification treatment asrequired. Specific examples thereof include, but are not particularlylimited to, publicly known surface treatment, such as degreasingtreatment with a surfactant, an organic solvent, an alkaline aqueoussolution, or the like, mechanical polishing treatment, immersiontreatment in an aqueous solution, preliminary electrolysis treatmentwith an electrolytic solution, water washing treatment, and dryingtreatment.

The metal oxide layer 13 is a support for supporting the dye. For themetal oxide layer 13, generally, one having a porous structure havingmany voids and a large surface area is used, and the metal oxide layer13 is preferably one that is fine and has few voids, and is morepreferably film-shaped. Particularly, the metal oxide layer 13 is morepreferably a structure in which porous fine particles adhere.

The metal oxide layer 13 in this embodiment is a porous semiconductorlayer comprising a metal oxide, such as titanium oxide, zinc oxide, tinoxide, niobium oxide, indium oxide, zirconium oxide, tantalum oxide,vanadium oxide, yttrium oxide, aluminum oxide, or magnesium oxide, asthe main component. Only one of these metal oxides may be used alone, ortwo or more of these metal oxides may be combined (mixed, a mixedcrystal, a solid solution, or the like) and used. For example, acombination of zinc oxide and tin oxide, titanium oxide and niobiumoxide, or the like can be used. In terms of obtaining high energyconversion efficiency, the metal oxide layer 13 is preferably a layersubstantially composed of titanium oxide or zinc oxide, more preferablya layer substantially composed of zinc oxide. Here, “substantiallycomposed of titanium oxide” means comprising 95 wt % or more of titaniumoxide, and “substantially composed of zinc oxide” means comprising 95 wt% or more of zinc oxide. The metal oxide layer 13 may comprise metals,such as titanium, tin, zinc, iron, tungsten, zirconium, strontium,indium, cerium, vanadium, niobium, tantalum, cadmium, lead, antimony,and bismuth, and metal oxides thereof and metal chalcogenides thereof.The thickness of the metal oxide layer 13 is not particularly limited,but is preferably 0.05 to 50 μm.

Examples of a method for forming the metal oxide layer 13 include, butare not particularly limited to, a method of providing a dispersion of ametal oxide on the conductive surface 12 a of the substrate 12 and thendrying it, a method of providing a dispersion or paste of a metal oxide(metal oxide slurry) on the conductive surface 12 a of the substrate 12and then high-temperature sintering it, and a method of providing adispersion or paste of a metal oxide on the conductive surface 12 a ofthe substrate 12 and then performing low-temperature treatment at about50 to 150° C., as well as a method of performing cathodeelectrodeposition on the conductive surface 12 a of the substrate 12from an electrolytic solution containing a metal salt. Here, when amethod that does not require high-temperature sintering is used, aplastic material having low heat resistance can be used as the substrate12, and therefore, the working electrode 11 having high flexibility canbe fabricated.

As a dye (sensitizing dye) that can inject electrons into a metal oxideby absorbing light and being excited, the dye in this embodimentdescribed above is supported (adsorbed) on the metal oxide layer 13.

The dye may include, in addition to the dye in this embodiment describedabove, other dyes (sensitizing dyes). One having the desired lightabsorption band and absorption spectrum can be applied according to theperformance required of the photoelectric conversion device.

Specific examples of the other dyes include an organic dye, such asxanthene, fluorescein, rhodamine, pyrogallol, dichlorofluorescein,Erythrosine B (Erythrosine is a registered trademark), fluorescin,Mercurochrome, a cyanine dye, a merocyanine dye, a trisazo dye, ananthraquinone dye, a polycyclic quinone dye, an indigo dye, adiphenylmethane dye, a trimethylmethane dye, a quinoline dye, abenzophenone dye, a naphthoquinone dye, a perylene dye, a fluorenonedye, a squarylium dye, an azulenium dye, a perinone dye, a quinacridonedye, a metal-free phthalocyanine dye, or a metal-free porphyrin dye. Inaddition, these other dyes preferably have an anchor group (for example,a carboxyl group, a sulfonic acid group, or a phosphoric acid group)that can be bonded or adsorbed on a metal oxide. Each of these otherdyes may be used alone, or a plurality of these other dyes may be usedin combination.

In addition, as the other dyes, for example, organometallic complexcompounds can also be used. Specific examples of the organometalliccomplex compounds include an organometallic complex compound having bothan ionic coordinate bond formed by a nitrogen anion in an aromaticheterocyclic ring and a metal cation, and a nonionic coordinate bondformed between a nitrogen atom or a chalcogen atom and a metal cation,and an organometallic complex compound having both an ionic coordinatebond formed by an oxygen anion or a sulfur anion and a metal cation, anda nonionic coordinate bond formed between a nitrogen atom or a chalcogenatom and a metal cation. More specific examples include a metalphthalocyanine dye, such as copper phthalocyanine or titanylphthalocyanine, a metal naphthalocyanine dye, a metal porphyrin dye, anda ruthenium complex, such as a bipyridyl ruthenium complex, a terpyridylruthenium complex, a phenanthroline ruthenium complex, a bicinchoninicacid ruthenium complex, an azo ruthenium complex, or a quinolinolruthenium complex. Each of these may be used alone, or a plurality ofthese may be used in combination.

In addition, the dye may comprise one or two or more additives. Examplesof the additives include an aggregation inhibitor for inhibiting theaggregation of the dye, specifically, a cholic acid compound representedby the following formula (XI). These may be used alone, or a pluralityof these may be mixed and used.

wherein R91 is an alkyl group having an acidic group; R92 represents agroup bonded to any of carbon atoms constituting a steroid skeleton inthe chemical formula, is a hydroxyl group, a halogen group, an alkylgroup, an alkoxy group, an aryl group, a heterocyclic group, an acylgroup, an acyloxy group, an oxycarbonyl group, an oxo group, or anacidic group, or a derivative thereof, and may be the same or different;t is an integer of 1 or more and 5 or less; and the bond between thecarbon atoms constituting the steroid skeleton in the chemical formulamay be a single bond or a double bond.

The method for supporting the dye on the metal oxide layer 13 is notparticularly limited. Specific examples thereof include a method ofimmersing the metal oxide layer 13 in a solution comprising the dye, anda method of applying a solution comprising the dye to the metal oxidelayer 13. The solvent of the dye-containing solution used here can beappropriately selected from publicly known solvents, for example, water,an ethanol solvent, a nitrile solvent, and a ketone solvent, accordingto the solubility, compatibility, or the like of the dye used.

Here, when the metal oxide layer 13 is formed by cathodeelectrodeposition, it is also possible to simultaneously perform theformation of the metal oxide layer 13 and dye support by using anelectrolytic solution comprising a metal salt and the dye, toimmediately form the dye-supported metal oxide electrode 14 in which thedye is supported (adsorbed) on the metal oxide surface of the metaloxide layer 13. The electrolysis conditions should be appropriately setaccording to the ordinary method according to the characteristics of thematerials used. For example, when the dye-supported metal oxideelectrode 14 composed of ZnO and the dye is formed, it is preferablethat the reduction electrolysis potential is about −0.8 to −1.2 V (vs.Ag/AgCl), the pH is about 4 to 9, and the bath temperature of theelectrolytic solution is about 0 to 100° C. In addition, it ispreferable that the metal ion concentration in the electrolytic solutionis about 0.5 to 100 mM, and the dye concentration in the electrolyticsolution is about 50 to 500 μM. Further, in order to further enhancephotoelectric conversion characteristics, it is possible to desorb thedye from the metal oxide layer 13 on which the dye is supported, once,and then readsorb another dye.

The working electrode 11 (metal oxide electrode 14) may have anintermediate layer between the conductive surface 12 a of the substrate12 and the metal oxide layer 13. The material of the intermediate layeris not particularly limited, but for example, the metal oxides describedfor the above transparent conductive film 12 a are preferable. Theintermediate layer can be formed by precipitating or depositing a metaloxide on the conductive surface 12 a of the substrate 12 by a publiclyknown method, for example, vapor deposition, CVD, spraying, spincoating, immersion, or electrodeposition. The intermediate layerpreferably has light transmission properties and further preferably hasconductivity. In addition, the thickness of the intermediate layer isnot particularly limited, but is preferably about 0.1 to 5 μm.

The counter electrode 21 functions as a positive electrode with respectto the external circuit. The counter electrode 21 is composed of asubstrate 22 having a conductive surface 22 a, and is opposed so thatthe conductive surface 21 a faces the metal oxide layer 13 of theworking electrode 11. For the substrate 22 and the conductive surface 22a, those publicly known can be appropriately used, as in the substrate12 and the conductive surface 12 a described above. For example, inaddition to the substrate 12 having conductivity, the transparentconductive film 12 a on the substrate 12, and a film (plate or foil) ofa metal, such as platinum, gold, silver, copper, aluminum, indium,molybdenum, titanium, rhodium, ruthenium, or magnesium, carbon, aconductive polymer, or the like further formed on the transparentconductive film 12 a of the substrate 12 can be used.

As the electrolyte 31, one generally used in a cell, a solar cell, orthe like, such as a redox electrolyte having a redox pair, a quasi-solidelectrolyte obtained by gelling this, or one obtained by forming ap-type semiconductor solid hole transport material into a film, can beappropriately used. For the electrolyte 31, one may be used alone, ortwo or more may be used in combination.

Examples of the redox electrolyte include an I⁻/I₃ ⁻ system, a Br⁻/Br₃ ⁻system, or a quinone/hydroquinone system, specifically, a combination ofa halide salt and a halogen simple substance, such as a combination ofan iodide salt and an iodine simple substance, or a combination of abromide salt and a bromine. The content of such a redox agent is notparticularly limited, but is preferably 1×10⁻⁴ to 1×10⁻² mol/g, morepreferably 1×10⁻³ to 1×10⁻² mol/g, with respect to the total amount ofthe electrolyte.

Examples of the above halide salt include cesium halides, quaternaryalkylammonium halides, imidazolium halides, thiazolium halides,oxazolium halides, quinolinium halides, or pyridinium halides. Morespecifically, examples of iodide salts thereof include cesium iodide,quaternary alkylammonium iodides, such as tetraethylammonium iodide,tetrapropylammonium iodide, tetrabutylammonium iodide,tetrapentylammonium iodide, tetrahexylammonium iodide,tetraheptylammonium iodide, or trimethylphenylammonium iodide,imidazolium iodides, such as 3-methylimidazolium iodide or1-propyl-2,3-dimethylimidazolium iodide, thiazolium iodides, such as3-ethyl-2-methyl-2-thiazolium iodide,3-ethyl-5-(2-hydroxyethyl)-4-methylthiazolium iodide, or3-ethyl-2-methylbenzothiazolium iodide, oxazolium iodides, such as3-ethyl-2-methyl-benzoxazolium iodide, quinolinium iodides, such as1-ethyl-2-methylquinolinium iodide, or pyridinium iodides. In addition,examples of bromide salts include quaternary alkylammonium bromides.Among combinations of a halide salt and a halogen simple substance, acombination of at least one of the above-described iodide salts and aniodine simple substance is preferable.

In addition, the redox electrolyte may be, for example, a combination ofan ionic liquid and a halogen simple substance. In this case, theabove-described halide salts or the like may be further contained. Forthe ionic liquid, one generally used in a cell, a solar cell, or thelike can be appropriately used, and the ionic liquid is not particularlylimited. Specific examples of the ionic liquid include those disclosedin “Inorg. Chem.” 1996, 35, p 1168 to 1178, “Electrochemistry” 2002, 2,p 130 to 136, National Publication of International Patent ApplicationNo. 9-507334, or Japanese Patent Laid-Open No. 8-259543.

The ionic liquid is preferably a salt having a melting point lower thanroom temperature (25° C.), or a salt that is liquefied at roomtemperature by dissolution with another molten salt or the like even ifit has a melting point higher than room temperature. Specific examplesof such an ionic liquid include anions and cations shown below.

Examples of ionic liquid cations include ammonium, imidazolium,oxazolium, thiazolium, oxadiazolium, triazolium, pyrrolidinium,pyridinium, piperidinium, pyrazolium, pyrimidinium, pyrazinium,triazinium, phosphonium, sulfonium, carbazolium, indolium, andderivatives thereof. Each of these may be used alone, or a plurality ofthese may be used in combination. Specific examples include1-methyl-3-propylimidazolium, 1-butyl-3-methylimidazolium,1,2-dimethyl-3-propylimidazolium, or 1-ethyl-3-methylimidazolium.

Examples of ionic liquid anions include a metal chloride, such as AlCl₄⁻ or Al₂Cl₇ ⁻, a fluorine-containing compound ion, such as PF₆ ⁻, BF₄ ⁻,CF₃SO₃ ⁻, N(CF₃SO₂)₂ ⁻, F(HF)_(n) ⁻, or CF₃COO⁻, a non-fluorine compoundion, such as NO₃ ⁻, CH₃COO⁻, C₆H₁₁COO⁻, CH₃OSO₃ ⁻, CH₃OSO₂ ⁻, CH₃SO₃ ⁻,CH₃SO₂ ⁻, (CH₃O)₂PO₂ ⁻, N(CN)₂ ⁻, or SCN⁻, or a halide ion, such as aniodide ion or a bromide ion. Each of these may be used alone, or aplurality of these may be used in combination. Among these, an iodideion is preferable as the ionic liquid anion.

The electrolyte 31 may be a liquid electrolyte (electrolytic solution)in which the above-described redox electrolyte is dissolved, dispersed,or suspended in a solvent, or a solid polymer electrolyte in which theabove-described redox electrolyte is held in a polymer substance. Inaddition, the electrolyte 31 may be a quasi-solid-like (paste-like)electrolyte comprising a redox electrolyte and a particulate conductivecarbon material, such as carbon black. Here, in this description, a“quasi-solid” means a concept including, in addition to a solid, agel-like solid or a clay-like solid whose flowability is hardly seen butwhich can be deformed by the application of stress, and specificallymeans one in which no or slight shape change occurs due to self-weightafter it is allowed to stand still and left for a certain time. Thequasi-solid-like electrolyte comprising a conductive carbon materialneed not comprise a halogen simple substance because the conductivecarbon material has the function of catalyzing a redox reaction.

The electrolyte 31 may comprise an organic solvent in which theabove-described halide salt or ionic liquid or the like is to bedissolved, dispersed, swelled, or suspended. The organic solvent can beused without particular limitation as long as it is electrochemicallyinert, but an organic solvent having a melting point of 20° C. or lessand a boiling point of 80° C. or more is preferable. By using an organicsolvent having a melting point and a boiling point in this range, thedurability tends to be enhanced. In addition, an organic solvent havinghigh viscosity is preferable. Since high viscosity provides a highboiling point, electrolyte leakage tends to be inhibited even under ahigh-temperature environment. Further, an organic solvent having highelectrical conductivity is preferable. Because of high electricalconductivity, high energy conversion efficiency tends to be obtained.

Specific examples of the organic solvent include hexane, benzene,toluene, quinoline, diethyl ether, chloroform, ethyl acetate,tetrahydrofuran, methylene chloride, acetone, acetonitrile,methoxyacetonitrile, propionitrile, butyronitrile, benzonitrile,3-methoxypropionitrile, valeronitrile, N,N-dimethylformamide, dimethylsulfoxide, sulfolane, acetic acid, formic acid, methanol, ethanol,1-propanol, 2-propanol, 1-butanol, pentanol, methyl ethyl ketone,dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate,propylene carbonate, ethylene glycol monoalkyl ether, propylene glycolmonoalkyl ether, polyethylene glycol monoalkyl ether, polypropyleneglycol monoalkyl ether, ethylene glycol, propylene glycol, polyethyleneglycol, polypropylene glycol, glycerin, dioxane, 1,4-dioxane, ethyleneglycol dialkyl ether, propylene glycol dialkyl ether, polyethyleneglycol dialkyl ether, polypropylene glycol dialkyl ether,N-methylpyrrolidone, γ-butyrolactone, α-methyl-γ-butyrolactone,β-methyl-γ-butyrolactone, γ-valerolactone, and 3-methyl-γ-valerolactone.Among these, an organic solvent having at least one of a nitrile group,a carbonate structure, a cyclic ester structure, a lactam structure, anamide group, an alcohol group, a sulfinyl group, a pyridine ring, and acyclic ether structure, as a functional group, is preferable becausewith an organic solvent having such a functional group, higher effectsare obtained than with an organic solvent comprising none of thesefunctional groups. Examples of the organic solvent having such afunctional group include acetonitrile, propylnitrile, butyronitrile,methoxyacetonitrile, methoxypropionitrile, dimethyl carbonate, ethylmethyl carbonate, ethylene carbonate, propylene carbonate,N-methylpyrrolidone, pentanol, quinoline, N,N-dimethylformamide,γ-butyrolactone, dimethyl sulfoxide, or 1,4-dioxane, particularly,methoxypropionitrile, propylene carbonate, N-methylpyrrolidone,pentanol, quinoline, N,N-dimethylformamide, γ-butyrolactone, dimethylsulfoxide, 1,4-dioxane, methoxyacetonitrile, and butyronitrile. Each ofthese organic solvents may be used alone, or a plurality of theseorganic solvents may be used in combination. In addition, the content ofthe organic solvent is preferably 10 to 80 wt % with respect to thetotal amount of the electrolyte 31.

The electrolyte 31 may comprise various additives according to therequired performance. For the additives, those generally used in a cell,a solar cell, or the like can be appropriately used. Specific examplesthereof include, but are not particularly limited to, a p-typeconductive polymer, such as polyaniline, polyacetylene, polypyrrole,polythiophene, polyphenylene, polyphenylenevinylene, and derivativesthereof; a molten salt composed of a combination of an imidazolium ion,a pyridinium ion, a triazolium ion, and derivatives thereof with ahalogen ion; a gelling agent; an oil gelling agent; a dispersing agent;a surfactant; and a stabilizer.

The method for disposing the electrolyte 31 between the workingelectrode 11 and the counter electrode 21 is not particularly limited,and various publicly known methods can be used. For example, thedye-supported metal oxide electrode 14, which is the working electrode11, and the conductive surface 22 a of the counter electrode 21 areopposed to each other at a predetermined interval via a spacer asrequired, and the peripheries are bonded to each other except apreviously formed injection port, using a sealing agent or the like, andthen, the whole is sealed. Then, the electrolyte is injected between theworking electrode 11 and the counter electrode 21 from the injectionport, and then, the injection port is sealed, and thus, the electrolyte31 can be formed.

When a solid charge transfer material is used as the electrolyte 31, anelectron transport material, a hole transport material, or the like ispreferably used.

As the hole transport material, for example, aromatic amines andtriphenylene derivatives are preferably used. Specific examples thereofinclude, but are not particularly limited to, an organic conductivepolymer, such as an oligothiophene compound, polypyrrole, polyacetyleneor a derivative thereof, poly(p-phenylene) or a derivative thereof,poly(p-phenylenevinylene) or a derivative thereof,polythienylenevinylene or a derivative thereof, polythiophene or aderivative thereof, polyaniline or a derivative thereof, orpolytoluidine or a derivative thereof.

In addition, as the hole transport material, for example, a p-typeinorganic compound semiconductor can also be used. In this case, ap-type inorganic compound semiconductor having a band gap of 2 eV ormore is preferably used, and a p-type inorganic compound semiconductorhaving a band gap of 2.5 eV or more is more preferable. In addition, itis necessary that the ionization potential of the p-type inorganiccompound semiconductor is smaller than the ionization potential of theworking electrode 11 from the conditions under which the holes of thedye can be reduced. Although the preferable range of the ionizationpotential of the p-type inorganic compound semiconductor is differentdepending on the dye used, the ionization potential is preferably in therange of 4.5 eV or more and 5.5 eV or less, more preferably in the rangeof 4.7 eV or more and 5.3 eV or less.

As the p-type inorganic compound semiconductor, for example, a compoundsemiconductor comprising monovalent copper is preferably used. Specificexamples of the compound semiconductor comprising monovalent copperinclude, but are not particularly limited to, CuI, CuSCN, CuInSe₂,Cu(In, Ga)Se₂, CuGaSe₂, Cu₂O, CuS, CuGaS₂, CuInS₂, CuAlSe₂, GaP, NiO,CoO, FeO, Bi₂O₃, MoO₂, and Cr₂O₃.

The method for forming the electrolyte 31 from the solid charge transfermaterial is not particularly limited, and various publicly known methodscan be used. When a hole transport material comprising an organicconductive polymer is used, a method, for example, vacuum deposition,casting, application, spin coating, immersion, electrolyticpolymerization, or photoelectrolytic polymerization, can be used. Inaddition, when an inorganic solid compound is used, a method, forexample, casting, application, spin coating, immersion, or electrolyticplating, can be used.

In the dye-sensitized solar cell 100 in this embodiment, when light(sunlight, or ultraviolet light, visible light, or near infrared lightequivalent to sunlight) is emitted to the working electrode 11, the dyeabsorbs the light, is excited, and injects electrons into the metaloxide layer 13. The injected electrons are transferred to the adjacentconductive surface 12 a, and then reach the counter electrode 21 via theexternal circuit. On the other hand, the electrolyte 31 is oxidized soas to return (reduce) the dye, which is oxidized with the electrontransfer, to the ground state. This oxidized electrolyte 31 is reducedby receiving the above electrons. In this manner, the electron transferbetween the working electrode 11 and the counter electrode 21 and theaccompanying redox reaction of the electrolyte 31 are repeated, andthus, continuous electron transfer occurs, and photoelectric conversionis steadily performed.

Here, in the dye-sensitized solar cell 100 in this embodiment, the dyehaving the structure represented by general formula (I) described aboveis used, and therefore, not only the absorption wavelength region iswider but also the energy transfer efficiency is better than those ofconventional ones. Therefore, the proportion of the amount of electronsinjected from the dye into the metal oxide layer 13 to the amount ofemitted light is high, and the energy conversion efficiency can beimproved. Especially, in the dye-sensitized solar cell 100 using theworking electrode 11 in which the metal oxide layer 13 is substantiallycomposed of zinc oxide, particularly the energy conversion efficiency isenhanced. Moreover, the dye having the structure represented by generalformula (I) described above has excellent adsorption properties(adhesiveness) on a metal oxide layer, and therefore, the durability ofthe dye-sensitized solar cell 100 is also enhanced.

EXAMPLES

Hereinafter, the present invention will be described in detail withSynthesis Examples, Examples, and Comparative Examples, but it should beconstrued that the invention is in no way limited to those examples.

First, dyes (1) to (17) according to the dyes described in the aboveembodiments and intermediates (a-1) to (a-12) were synthesized by thefollowing procedures.

Synthesis Example 1

An intermediate a-1 (0.13 mmol, 0.09 g), hemicyanine A (0.13 mmol, 0.05g), triethylamine (0.26 mmol, 0.03 g), acetic anhydride (0.20 mmol, 0.02g), and 1,2-dichloroethane (0.5 g) were put in, and heated to reflux for1 hour. After the solvents were distilled away, hydrochloric acid (0.1g) and acetic acid (1.0 g) were added to a reaction product, and thenthe resulting reaction product was stirred at 100° C. for 1 hour. Next,anion exchange was carried out using sodium iodide, and then, oil-waterseparation was carried out. After that, the resulting organic phase waspurified by PLC (using a mobile phase solvent of chloroform/methanol(10:1)), and thus, 40 mg of a final product, dye (1), was obtained.

Synthesis Example 2

An intermediate a-1 (0.13 mmol, 0.09 g), hemicyanine B (0.13 mmol, 0.06g), triethylamine (0.26 mmol, 0.03 g), acetic anhydride (0.20 mmol, 0.02g), and 1,2-dichloroethane (0.5 g) were put in, and heated to reflux for1 hour. After the solvents were distilled away, hydrochloric acid (0.1g) and acetic acid (1.0 g) were added to a reaction product, and thenthe resulting reaction product was stirred at 100° C. for 1 hour. Next,anion exchange was carried out using sodium iodide, and then, oil-waterseparation was carried out. After that, the resulting organic phase waspurified by PLC (using a mobile phase solvent of chloroform/methanol(10:1)), and thus, 40 mg of a final product, dye (2), was obtained.

Synthesis Example 3

A final product, dye (3), was obtained by the same process as that inSynthesis Example 1 except that an intermediate a-2 was used instead ofintermediate a-1.

Synthesis Example 4

A final product, dye (4), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-2 was used instead ofintermediate a-1.

Synthesis Example 5

A final product, dye (5), was obtained by the same process as that inSynthesis Example 1 except that an intermediate a-3 was used instead ofintermediate a-1.

Synthesis Example 6

A final product, dye (6), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-3 was used instead ofintermediate a-1.

Synthesis Example 7

An intermediate a-4 (0.13 mmol, 0.10 g), hemicyanine C (0.13 mmol, 0.05g), triethylamine (0.26 mmol, 0.03 g), acetic anhydride (0.20 mmol, 0.02g), and 1,2-dichloroethane (0.5 g) were put in, and heated to reflux for1 hour. After the solvents were distilled away, hydrochloric acid (0.1g) and acetic acid (1.0 g) were added to a reaction product, and thenthe resulting reaction product was stirred at 100° C. for 1 hour. Next,anion exchange was carried out using sodium iodide, and then, oil-waterseparation was carried out. After that, the resulting organic phase waspurified by PLC (using a mobile phase solvent of chloroform/methanol(10:1)), and thus, 3 mg of a final product, dye (7), was obtained.

Synthesis Example 8

A final product, dye (8), was obtained by the same process as that inSynthesis Example 7 except that an intermediate a-5 was used instead ofintermediate a-4.

Synthesis Example 9

A final product, dye (9), was obtained by the same process as that inSynthesis Example 1 except that an intermediate a-6 was used instead ofintermediate a-1.

Synthesis Example 10

A final product, dye (10), was obtained by the same process as that inSynthesis Example 1 except that an intermediate a-7 was used instead ofintermediate a-1.

Synthesis Example 11

A final product, dye (11), was obtained by the same process as that inSynthesis Example 1 except that an intermediate a-8 was used instead ofintermediate a-1.

Synthesis Example 12

A final product, dye (12), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-9 was used instead ofintermediate a-1.

Synthesis Example 13

A final product, dye (13), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-10 was used instead ofintermediate a-1.

Synthesis Example 14

A final product, dye (14), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-11 was used instead ofintermediate a-1.

Synthesis Example 15

A final product, dye (15), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-4 was used instead ofintermediate a-1.

Synthesis Example 16

An intermediate a-3 (0.18 mmol, 0.15 g), a bridging agent (0.09 mmol,0.026 g), triethylamine (0.19 mmol, 0.019 g), acetic anhydride (0.19mmol, 0.019 g), and 1,2-dichloroethane (0.5 g) were put in, and heatedto reflux for 1 hour. After the solvents were distilled away,hydrochloric acid (0.1 g) and acetic acid (1.0 g) were added to areaction product, and then the resulting reaction product was stirred at100° C. for 1 hour. After performing oil-water separation, the resultingorganic phase was purified by PLC (using a mobile phase solvent ofchloroform/methanol (10:1)), and thus, 8 mg of a final product, dye(16), was obtained.

Synthesis Example 17

A final product, dye (17), was obtained by the same process as that inSynthesis Example 2 except that an intermediate a-12 was used instead ofintermediate a-1.

Synthesis Example 18

First, a yellow dye A (1.0 mmol, 0.50 g) and chloroform (5 ml) were putin, and then, oxalyl chloride (1.1 mmol, 0.14 g) and dimethylformamide(0.1 ml) were added thereto in this order, and the resulting mixture wasstirred at room temperature for 1 hour. After the mixture was cooled to10° C., 5-aminoindolenine (1.0 mmol, 0.17 g) and triethylamine (2.0mmol, 0.20 g) were added thereto, and the resulting mixture was stirredat room temperature for 2 hours. Oil-water separation was performedafter addition of water (5 ml), and then, the resulting organic phasewas purified by PLC (using a mobile phase solvent of chloroform/methanol(10:1)), and thus, 0.53 g of the objective indolenine A was obtained. Inthis way, an indolenine compound having an amide bond (or sulfonamidebond) was obtained by the corresponding amino compound and thecorresponding carboxylic acid (or sulfonic acid) compound, and thefollowing indolenine B to L were synthesized by the same process.

Next, indolenine A (0.81 mmol, 0.53 g) and methyl para-toluenesulfonate(1.2 mmol, 0.22 g) were put in, and the resulting mixture was stirred at100° C. for 2 hours. After the mixture was cooled to room temperature,the reaction solution was purified by PLC (using a mobile phase solventof chloroform/methanol (10:1)), and thus, 0.19 g of the objectiveintermediate (a-1) was obtained.

Synthesis Example 19

The objective intermediate (a-2) was obtained by the same process asthat in Synthesis Example 18 except that indolenine B and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

Synthesis Example 20

The objective intermediate (a-3) was obtained by the same process asthat in Synthesis Example 18 except that indolenine C and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively, and anion exchange with iodineanion was carried out after reaction.

Synthesis Example 21

The objective intermediate (a-4) was obtained by the same process asthat in Synthesis Example 18 except that indolenine D and iodobutanewere used instead of indolenine A and methyl para-toluenesulfonate,respectively.

Synthesis Example 22

The objective intermediate (a-5) was obtained by the same process asthat in Synthesis Example 18 except that indolenine E and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

Synthesis Example 23

The objective intermediate (a-6) was obtained by the same process asthat in Synthesis Example 18 except that indolenine F and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

Synthesis Example 24

The objective intermediate (a-7) was obtained by the same process asthat in Synthesis Example 18 except that indolenine G and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

Synthesis Example 25

The objective intermediate (a-8) was obtained by the same process asthat in Synthesis Example 18 except that indolenine H was used insteadof indolenine A.

Synthesis Example 26

The objective intermediate (a-9) was obtained by the same process asthat in Synthesis Example 18 except that indolenine I was used insteadof indolenine A, and anion exchange with bromine anion was carried outafter reaction.

Synthesis Example 27

The objective intermediate (a-10) was obtained by the same process asthat in Synthesis Example 18 except that indolenine J and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

Synthesis Example 28

The objective intermediate (a-11) was obtained by the same process asthat in Synthesis Example 18 except that indolenine K and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

Synthesis Example 29

The objective intermediate (a-12) was obtained by the same process asthat in Synthesis Example 18 except that indolenine L and ethylbromopropionate were used instead of indolenine A and methylpara-toluenesulfonate, respectively.

The structures of dyes (1) to (17) which were the final products inSynthesis Examples 1 to 17 and intermediates (a-1) to (a-12) obtained inSynthesis Examples 18 to 29 were identified by a nuclear magneticresonance (NMR) method. In addition, for each of dyes (1) to (17) whichwere the final products in Synthesis Examples 1 to 17, a maximumabsorption wavelength (λmax) was measured. The results are shown inTables 1 to 4.

It is noted that Lambda-400 manufactured by JEOL Ltd. was used as ameasuring device in the NMR measurement. In this case, a solutionprepared by dissolving 3 to 10 mg of the final product in 1 cm³ of adeuterated solvent was used as a measurement sample, and a ¹H-NMRspectrum was measured at room temperature.

Moreover, for the measurement of the maximum absorption wavelength(λmax), a UV spectrometer (U-3010) manufactured by Hitachi, Ltd. wasused. In this case, a measurement sample prepared by adding the finalproduct to methanol (CH₃OH; solvent) so that the absorbance was in therange of 0.5 to 1.0 was used for the measurement.

TABLE 1 Synthesis Example ¹H NMR Synthesis 10.65 (s, 1H), 8.40 (t, 1H),8.27 (d, 1H), 8.06 (t, 2H), 7.89 (d, 1H), Example 1 7.85 (d, 1H), 7.87(d, 1H), 7.68-7.61 (m, 2H), 7.52-7.42 (m, 3H), 7.29 (d, 1H), (DMSO-d6)6.48 (t, 2H), 5.51 (d, 1H), 4.87 (s, 2H), 4.39 (t, 2H), 3.97 (t, 2H),3.64 (s, 3H), 2.49 (t, 2H), 1.95 (s, 6H), 1.67-1.50 (m, 15H), 1.00 (d,6H) Synthesis 10.85 (s, 1H), 8.63 (d, 1H), 8.50 (d, 1H), 8.24 (d, 1H),8.11-8.05 (m, 3H), Example 2 7.88-7.83 (m, 3H), 7.71-7.66 (m, 2H), 7.54(t, 2H), 7.44 (d, 1H), 7.29 (d, (DMSO-d6) 1H), 6.38 (d, 1H), 6.24 (d,1H), 5.51 (d, 1H), 4.88 (s, 2H), 4.50 (t, 2H), 3.96 (t, 2H), 3.72 (s,3H), 2.67 (t, 2H), 1.94 (s, 6H), 1.73-1.50 (m, 15H), 1.00 (d, 6H)Synthesis 9.03 (s, 1H), 8.33 (s, 1H), 8.18 (s, 1H), 7.96 (d, 3H), 7.89(d, 1H), 7.77 (d, Example 3 2H), 7.69 (d, 1H), 7.39 (d, 1H), 7.33 (d,1H), 6.71 (d, 3H), 6.65 (d, 3H), (CDCl₃) 4.42-4.59 (m, 4H) 3.52-3.41 (m,4H), 2.82 (t, 4H), 1.26-1.17 (m, 18H) Synthesis 8.58 (d, 1H), 8.47 (d,1H), 8.22 (d, 1H), 8.11-8.01 (m, 4H), 7.90-7.85 (m, Example 4 3H), 7.66(t, 2H), 7.53 (d, 2H), 6.80 (d, 2H), 6.39 (d, 2H), 4.52-4.39 (m,(DMSO-d6) 4H), 3.46 (b, 4H), 2.65 (t, 4H), 1.91 (s, 6H), 1.69 (s, 6H),1.13 (t, 6H) Synthesis 10.52 (s, 1H), 8.39 (t, 1H), 8.26-8.23 (m, 2H),8.04 (s, 2H), 7.88-7.85 (m, Example 5 2H), 7.72 (d, 1H), 7.62 (t, 1H),7.50-7.41 (m, 4H), 7.31 (t, 1H), (DMSO-d6) 7.14-7.08 (m, 2H), 6.60-6.50(m, 2H), 4.85 (s, 2H), 4.44 (t, 2H), 4.32 (t, 2H), 3.92 (t, 2H),2.65-2.58 (m, 4H), 1.93 (s, 6H), 1.68-1.54 (m, 13H), 1.01-0.91 (m, 8H)Synthesis 10.61 (s, 1H), 8.48 (d, 1H), 8.21 (d, 1H), 8.08 (d, 1H), 8.05(d, 1H), Example 6 7.95 (s, 1H), 7.88-7.84 (m, 2H), 7.67 (t, 1H), 7.51(d, 2H), 7.43 (d, 2H), (DMSO-d6) 7.28 (d, 1H), 7.13-7.06 (m, 3H),6.40-6.36 (m, 3H), 4.86 (s, 2H), 4.54 (t, 2H), 4.40 (t, 2H), 3.92 (t,2H), 2.70-2.60 (m, 4H), 1.89 (s, 6H), 1.73-1.56 (m, 13H), 1.01-0.96 (m,8H) Synthesis 8.51 (t, 1H), 8.10 (d, 2H), 7.97-7.92 (m, 4H), 7.60 (t,1H), 7.42-7.33 (m, Example 7 3H), 7.25-7.22 (m, 3H), 7.04-6.99 (m, 2H),6.61-6.55 (m, 2H), 5.00 (s, (CDCl₃) 2H), 4.15-4.12 (m, 4H), 3.86 (s,3H), 2.85 (t, 2H), 1.77 (s, 6H), 1.75 (s, 6H), 1.46 (m, 2H), 1.25 (s,6H), 1.03 (t, 2H), 0.88 (t, 3H) Synthesis 8.60 (t, 1H), 8.23 (d, 1H),8.09 (d, 1H), 7.93-7.80 (m, 4H), 7.78 (d, 1H), Example 8 7.65-7.42 (m,6H), 7.21 (d, 2H), 7.06 (t, 1H), 6.99-6.90 (m, 2H), 6.82 (d (CDCl₃) 1H),5.18 (s, 2H), 4.51 (t, 2H), 3.86 (s, 3H), 3.72 (t, 2H), 3.05 (t, 2H),1.97 (s, 6H), 1.61 (s, 6H), 1.42 (m, 1H), 1.02 (s, 6H), 0.92-0.86 (m,8H) Synthesis 8.60 (t, 1H), 8.25 (d, 1H), 8.00 (m, 3H), 7.72-7.38 (m,8H), 6.88 (d, 2H), Example 9 6.48 (m, 3H), 4.38 (m, 4H), 3.41 (t, 3H),2.69 (m, 4H), 2.03 (s, 6H), (CD₃OD) 1.79 (s, 6H), 1.17 (t, 3H) Synthesis8.55 (m, 1H), 8.16 (d, 1H), 7.89 (t, 2H), 7.56 (d, 1H), 7.53 (t, 3H),Example 10 7.42-7.24 (m, 7H), 7.05 (d, 2H), 6.61 (d, 2H), 6.45 (m, 2H),4.41 (d, 2H), (CD₃OD) 4.29 (d, 2H), 2.91 (s, 6H), 2.57 (m, 4H), 1.95 (s,6H), 1.19 (s, 6H)

TABLE 2 Synthesis 8.54 (m, 1H), 8.22 (d, 1H), 8.01 (t, 2H), 7.80 (m,2H), 7.69 (d, 1H), 7.64 (t, Example 11 1H), 7.20-7.12 (m, 3H), 6.78 (d,2H), 6.51 (d, 2H), 6.33 (d, 2H), 4.45 (m, (CD₃OD) 4H), 3.61 (s, 3H),3.06 (s, 6H), 2.64 (m, 4H), 2.01 (s, 6H), 1.74 (s, 6H) Synthesis 8.52(d, 2H), 8.17 (d, 1H), 7.99-7.93 (m, 2H), 7.80 (s, 1H), 7.79-7.59 (m,Example 12 9H), 7.50 (d, 2H), 7.48 (t, 1H), 7.31 (t, 2H), 7.08 (d, 1H),6.74 (d, 2H), (CD₃OD) 6.69 (d, 2H), 6.55 (d, 1H), 6.29 (d, 1H), 4.56 (t,2H), 3.71 (d, 1H), 3.56 (d, 1H), 3.36 (s, 3H), 3.20 (s, 6H), 2.71 (t,2H), 1.94 (s, 6H), 1.87 (s, 3H) Synthesis 8.51 (d, 1H), 8.41 (d, 1H),8.24 (d, 1H), 8.07-7.99 (m, 4H), 7.78 (d, 1H), Example 13 7.66 (t, 1H),7.52-7.46 (m, 4H), 7.00-6.96 (m, 3H), 6.51 (d, 1H), 6.46 (d, (CD₃OD)1H), 4.59 (t, 2H), 4.46 (t, 2H), 2.73 (t, 2H), 2.68 (t, 2H), 2.00 (s,6H), 1.76 (s, 6H) Synthesis 8.53 (d, 1H), 8.43 (d, 1H), 8.26 (d, 1H),8.06 (d, 1H), 8.02 (d, 1H), 7.95 (s, Example 14 1H), 7.83-7.79 (m, 2H),7.69-7.53 (m, 5H), 7.37 (d, 3H), 6.56 (d, 1H), (CD₃OD) 6.49 (d, 1H),4.91 (s, 2H), 4.60 (t, 2H), 4.47 (t, 2H), 4.15 (q, 2H), 2.74 (t, 2H),2.69 (t, 2H), 2.58 (d, 2H), 2.01 (s, 6H), 1.90 (s, 6H), 1.33-1.23 (m,4H), 0.96 (d, 6H) Synthesis 8.50 (d, 1H), 8.42 (d, 1H), 8.23 (d, 1H),8.04 (d, 1H), 8.01 (d, 1H), 7.94 (s, Example 15 1H), 7.91-7.87 (m, 4H),7.78 (d, 1H), 7.66 (t, 1H), 7.52 (d, 1H), 7.47 (d, (CD₃OD) 1H),7.41-7.39 (m, 2H), 7.23-7.21 (m, 2H), 6.54 (d, 1H), 6.40 (d, 1H), 4.96(s, 2H), 4.60 (t, 2H), 4.26-4.19 (m, 4H), 2.82 (t, 2H), 2.74 (t, 2H),2.00 (s, 6H), 1.85 (t, 2H) 1.75-1.71 (m, 12H), 1.52 (m, 2H), 1.04 (m,3H) Synthesis 8.31 (d, 2H), 7.92 (d, 2H), 7.82 (s, 2H), 7.59-7.51 (m,4H), 7.42 (d, 2H), Example 16 7.37 (d, 2H) 7.26-7.18 (m, 4H), 7.02-6.94(m, 4H), 6.39 (d, 2H), 4.86 (s, (CD₃OD) 4H), 4.41 (t, 4H), 3.81 (t, 4H),2.19 (t, 4H), 2.17 (t, 4H), 1.64-1.50 (m, 26H), 0.97 (s, 12H) Synthesis8.53 (s, 1H), 8.25 (d, 2H), 8.09-8.01 (m, 4H), 7.75-7.78 (m, 2H),Example 17 7.70-7.64 (m, 6H), 7.58-7.51 (m, 6H), 7.24 (d, 1H), 6.61 (d,1H), 6.34 (d, 1H), (CD₃OD) 5.91 (s, 1H), 4.66-4.58 (m, 4H), 4.38 (t,2H), 4.06 (q, 2H), 3.94 (s, 3H), 2.80-2.75 (m, 6H), 1.87 (s, 12H), 1.28(s, 6H), 1.17 (t, 3H) Synthesis 7.94 (d, 1H), 7.55 (d, 1H), 7.48-7.38(m, 3H), 7.11 (d, 1H), 6.87 (d, 1H), Example 18 5.28 (d, 1H), 4.93 (s,2H), 3.83 (s, 2H), 3.76 (t, 2H), 3.02 (s, 2H), (CDCl₃) 1.75-1.60 (m,9H), 1.32 (s, 6H), 1.07 (d, 6H) Synthesis 8.37 (s, 1H), 8.27 (s, 1H),8.20 (s, 1H), 7.93 (d, 2H), 7.70 (d, 1H), 7.62 (d, Example 19 2H), 6.69(d, 2H), 5.08 (t, 2H), 4.06 (q, 2H), 3.46 (q, 4H), 3.14 (t, 2H), (CDCl₃)3.10 (s, 3H), 1.62 (s, 6H), 1.26-1.19 (m, 9H) Synthesis 10.43 (s, 1H),8.14 (s, 1H), 7.90 (d, 1H), 7.73 (m, 2H), 7.51 (d, 2H), Example 20 7.05(m, 2H), 6.82 (m, 2H), 5.22 (s, 2H), 4.04 (q, 2H), 3.75 (m, 4H), 3.14(t, (CDCl₃) 2H), 2.99 (s, 3H), 1.63 (s, 6H), 1.47-1.44 (m, 9H), 1.19 (t,3H), 1.05 (s, 6H)

TABLE 3 Synthesis 7.74 (d, 2H), 7.44-7.39 (m, 2H), 7.28-7.24 (m, 2H),7.09-7.01 (m, 3H), Example 21 6.59 (d, 1H), 5.42 (d, 2H), 4.20-4.14 (m,4H), 3.98 (q, 2H), 2.69-2.66 (m, (DMSO-d6) 5H), 1.56-1.50 (m, 14H),1.10-1.04 (m, 5H), 0.87 (t, 3H) Synthesis 8.11 (s, 1H), 8.09 (d, 1H),7.65-7.57 (m, 2H), 7.48-7.36 (m, 4H), Example 22 7.15-7.08 (m, 2H),6.86-6.84 (m, 2H), 5.11 (s, 2H), 4.02 (q, 2H), 3.75 (m, 4H), (CDCl₃)2.63 (s, 2H), 2.45 (t, 2H), 1.73-1.52 (m, 12H), 1.22-1.12 (m, 6H),1.06-0.90 (m, 6H) Synthesis 7.63 (d, 1H), 7.53 (s,1H), 7.41 (d, 2H),7.19 (d, 1H), 6.63 (d, 2H), 6.54 (d, Example 23 1H), 6.25 (d, 1H), 4.09(t, 4H), 3.9-3.83 (m, 5H), 3.4-3.32 (m, 8H), 2.56 (t, (CDCl₃) 2H),1.22-1.14 (m, 9H) Synthesis 7.83 (d, 1H), 7.65-7.10 (m, 6H), 6.93 (t,1H), 6.65-6.40 (m, 3H), 4.10 (m, Example 24 2H), 3.90 (t, 2H), 3.10-2.97(m, 9H), 2.27 (t, 2H), 1.38-1.20 (m, 9H) (CD₃OD) Synthesis 10.75 (s,1H), 7.90 (d, 2H), 7.83-7.73 (m, 5H), 7.47 (m, 3H), 7.22 (d, 1H),Example 25 7.07 (d, 2H), 6.81 (d, 2H), 3.88 (s, 3H), 3.07 (s, 6H), 2.66(s, 3H), 2.27 (s, (DMSO-d6) 3H), 1.43 (s, 6H) Synthesis 10.29 (s, 1H),7.88 (d, 2H), 7.78-7.72 (m, 8H), 6.92 (d, 2H), 6.83-6.80 (m, Example 264H), 3.86 (s, 3H), 3.61 (d, 1H), 3.53 (d, 1H), 3.03 (s, 6H), 2.96 (s,3H), (DMSO-d6) 1.67 (s, 3H) Synthesis 10.81 (s, 1H), 8.13 (s, 1H), 7.92(d, 1H), 7.75 (d, 1H), 7.73 (d, 1H), 7.48 (d, Example 27 1H), 7.21 (d,1H), 6.97 (d, 1H), 4.64 (t, 2H), 4.05 (q, 2H), 3.05 (t, 2H), (DMSO-d6)2.82 (s, 3H), 1.52 (s, 6H), 1.15 (t, 3H) Synthesis 11.03 (s, 1H), 8.05(s, 1H), 7.96 (d, 1H), 7.87 (s, 1H), 7.67-7.62 (m, 3H), Example 28 7.42(d, 2H), 4.99 (s, 2H), 4.64 (t, 2H), 4.09-4.03 (m, 4H), 3.04 (t, 2H),(DMSO-d6) 2.82 (s, 3H), 2.50 (d, 2H), 1.90 (sep, 1H), 1.49 (s, 6H),1.83-1.65 (m, 6H), 0.89 (d, 6H) Synthesis 9.08 (s, 1H), 7.95 (d, 2H),7.65-7.57 (m, 4H), 7.51-7.43 (m, 4H), Example 29 7.37-7.31 (m, 3H), 6.34(d, 1H), 4.67 (t, 3H), 4.06 (q, 2H) 3.79 (t, 2H), 3.71 (CDCl₃) (t, 2H),3.11 (t, 2H), 2.88 (s, 3H), 2.51 (t, 2H), 2.09 (s, 6H), 1.19 (s, 6H),1.18 (t, 3H)

TABLE 4 Synthesis Example Yield/% λmax MeOH/nm 1 29 582 2 27 648 3 1 5904 16 654 5 5 584 6 8 650 7 2 582 8 3 587 9 6 592, 10 1 588 11 2 578 12 6639 13 6 656 14 3 650 15 1 650 16 6 649 17 22 650 18 35 — 19 63 — 20 26— 21 47 — 22 5 — 26 52 — 27 33 — 28 10 — 29 48 —

It was confirmed that compounds having structures of dyes (1) to (17)and intermediates (a-1) to (a-12) were synthesized in Synthesis Examples1 to 29, respectively, as shown in Tables 1 to 3 and Table 4.

Next, the dye-sensitized solar cells 100 described in the aboveembodiments were produced by the following procedures.

Example 1

By using dye (1) obtained in Synthesis Example 1, a dye-sensitized solarcell 100 equivalent to that described in the above embodiments wasproduced by the following procedure.

First, a working electrode 11 was produced by the following procedure.

First, as a base 12 having a conductive surface 12 a, a conductive glasssubstrate (F—SnO₂) having a transparent conductive film offluorine-doped SnO and having a size of 2.0 cm in length×1.5 cm inwidth×1.1 mm in thickness was prepared. Next, masking tape having athickness of 70 μm was placed on the conductive surface 12 a so as tosurround a square portion having a size of 0.5 cm in length×0.5 cm inwidth, and then, 3 cm³ of a metal oxide slurry was applied on theportion with a constant thickness and dried. As the metal oxide slurry,one prepared by suspending a zinc oxide powder (average particle size 20nm; FINEX-50 manufactured by Sakai Chemical Industry Co., Ltd.) in waterso that the amount of the zinc oxide powder was 10% by weight was used,the water having one drop of a non-ionic surfactant, Triton X-100(Triton is registered trademark), added therein. Next, the masking tapeon the conductive surface 12 a was peeled off, and then, the base 12 wasburned at 450° C. using an electric furnace, thus forming a zinc oxidefilm having a thickness of about 5 μm serving as a metal oxide layer 13.Next, a dye-containing solution was prepared by dissolving dye (1) anddeoxycholic acid in dehydrated ethanol so that their concentrations were3×10⁻⁴ mol/dm³ and 1×10⁻² mol/dm³, respectively. Then, the base 12having the metal oxide layer 13 formed thereon was immersed in thedye-containing solution to allow dye (1) to be supported on the metaloxide layer 13 to form a dye-supported metal oxide electrode 14, andthus, a working electrode 11 of Example 1 was obtained.

Next, a counter electrode 21 was produced by the following procedure.

First, as a base 22 having a conductive surface 22 a, a conductive glasssubstrate (F—SnO₂) having a transparent conductive film offluorine-doped SnO and having a size of 2.0 cm in length×1.5 cm inwidth×1.1 mm in thickness was prepared. Next, a Pt layer having athickness of 100 nm was formed on the conductive surface 22 a bysputtering, and thus, a counter electrode 21 was obtained. It is notedthat, in this case, two holes (φ1 mm) for injecting an electrolytesolution were preliminarily formed in the base 22 having the conductivesurface 22 a.

Next, the electrolyte solution was prepared by adding dimethylhexylimidazolium iodide (0.6 mol/dm³), lithium iodide (0.1 mol/dm³), andiodine (0.05 mol/dm³) to acetonitrile at the prescribed concentrationsand performing mixing.

After that, the dye-sensitized solar cell 100 was produced by using theworking electrode 11, the counter electrode 21, and the electrolytesolution by the following procedure.

First, spacers having a thickness of 50 μm were placed so as to surroundthe metal oxide layer 13, and after that, the dye-supported metal oxideelectrode 14 of the working electrode 11 and the Pt layer of the counterelectrode 21 were placed with facing each other, and bonded via thespacers. After that, the electrolyte solution was injected through theinjecting holes formed in the counter electrode 21, to form anelectrolyte 31. Finally, all around the cell and the injecting holeswere sealed, and thus, the dye-sensitized solar cell 100 of Example 1was obtained.

Example 2

A working electrode 11 and a dye-sensitized solar cell 100 of Example 2were produced by the same process as that in Example 1 except that ametal oxide slurry containing a titanium oxide (TiO₂) powder describedbelow was used instead of the metal oxide slurry containing a zinc oxidepowder, Triton X-100, and water, to form a titanium oxide film, in theformation of the metal oxide layer 13 by burning.

The metal oxide slurry containing a titanium oxide powder was preparedas follows. First, 125 cm³ of titanium isopropoxide was added to 750 cm³of 0.1 mol/dm³ nitric acid aqueous solution with performing stirring,and stirring was carried out vigorously at 80° C. for 8 hours. Theresulting liquid was poured into a teflon (registered trademark)pressure container, and the pressure container was treated in anautoclave at 230° C. for 16 hours. After that, the liquid (sol liquid)after the autoclave treatment containing precipitates was stirred to beresuspended. Next, the resulting suspension was filtered under vacuum toremove non-resuspended precipitates, and sol filtrate was concentratedso as to have a titanium oxide concentration of 11% by mass using anevaporator. After that, in order to improve wettability of theconcentrated solution to the substrate, a drop of Triton X-100 wasadded. Next, a titanium oxide powder having an average particle size of30 nm (P-25 manufactured by Nippon Aerosil Co., Ltd.) was added to theconcentrated solution so that the entire content of titanium oxide was33% by mass, and dispersed for 1 hour by centrifugal mixing usingrotation and revolution, thus preparing the metal oxide slurrycontaining the titanium oxide powder.

Examples 3 and 4

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 3and 4 were obtained by the same process as those in Examples 1 and 2except that dye (5) was used instead of dye (1), respectively.

Examples 5 and 6

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 5and 6 were obtained by the same process as those in Examples 1 and 2except that dye (8) was used instead of dye (1), respectively.

Examples 7 and 8

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 7and 8 were obtained by the same process as those in Examples 1 and 2except that dye (3) was used instead of dye (1), respectively.

Examples 9 and 10

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 9and 10 were obtained by the same process as those in Examples 1 and 2except that dye (9) was used instead of dye (1), respectively.

Examples 11 and 12

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 11and 12 were obtained by the same process as those in Examples 1 and 2except that dye (10) was used instead of dye (1), respectively.

Examples 13 and 14

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 13and 14 were obtained by the same process as those in Examples 1 and 2except that dye (2) was used instead of dye (1), respectively.

Examples 15 and 16

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 15and 16 were obtained by the same process as those in Examples 1 and 2except that dye (6) was used instead of dye (1), respectively.

Examples 17 and 18

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 17and 18 were obtained by the same process as those in Examples 1 and 2except that dye (14) was used instead of dye (1), respectively.

Examples 19 and 20

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 19and 20 were obtained by the same process as those in Examples 1 and 2except that dye (16) was used instead of dye (1), respectively.

Examples 21 and 22

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 21and 22 were obtained by the same process as those in Examples 1 and 2except that dye (4) was used instead of dye (1), respectively.

Examples 23 and 24

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 23and 24 were obtained by the same process as those in Examples 1 and 2except that dye (13) was used instead of dye (1), respectively.

Examples 25 and 26

Working electrodes 11 and dye-sensitized solar cells 100 of Examples 25and 26 were obtained by the same process as those in Examples 1 and 2except that dye (17) was used instead of dye (1), respectively.

Comparative Examples 1 and 2

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 1 and 2 were obtained by the same process as those in Examples1 and 2 except that 3.0×10⁻⁴ mol/dm³ of dye (C1) and 3.0×10⁻⁴ mol/dm³ ofdye (C2) were used instead of dye (1), respectively.

Comparative Examples 3 and 4

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 3 and 4 were obtained by the same process as those in Examples3 and 4 except that 3.0×10⁻⁴ mol/dm³ of a dye (C3) and 3.0×10⁻⁴ mol/dm³of a dye (C4) were used instead of dye (5), respectively.

Comparative Examples 5 and 6

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 5 and 6 were obtained by the same process as those in Examples5 and 6 except that 3.0×10⁻⁴ mol/dm³ of a dye (C3) and 3.0×10⁻⁴ mol/dm³of a dye (C2) were used instead of dye (8), respectively.

Comparative Examples 7 and 8

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 7 and 8 were obtained by the same process as those in Examples19 and 20 except that 3.0×10⁻⁴ mol/dm³ of dye (C5) was used instead ofdye (16), respectively.

Comparative Examples 9 and 10

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 9 and 10 were obtained by the same process as those in Examples7 and 8 except that 3.0×10⁻⁴ mol/dm³ of a dye (C6) and 3.0×10⁻⁴ mol/dm³of a dye (C4) were used instead of dye (3), respectively.

Comparative Examples 11 and 12

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 11 and 12 were obtained by the same process as those inExamples 11 and 12 except that 3.0×10⁻⁴ mol/dm³ of a dye (C8) and3.0×10⁻⁴ mol/dm³ of a dye (C4) were used instead of dye (10),respectively.

Comparative Examples 13 and 14

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 13 and 14 were obtained by the same process as those inExamples 13 and 14 except that 3.0×10⁻⁴ mol/dm³ of dye (C1) and 3.0×10⁻⁴mol/dm³ of dye (C8) were used instead of dye (2), respectively.

Comparative Examples 15 and 16

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 15 and 16 were obtained by the same process as those inExamples 15 and 16 except that 3.0×10⁻⁴ mol/dm³ of a dye (C9) was usedinstead of dye (6), respectively.

Comparative Examples 17 and 18

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 17 and 18 were obtained by the same process as those inExamples 17 and 18 except that 3.0×10⁻⁴ mol/dm³ of a dye (C10) was usedinstead of dye (14), respectively.

Comparative Examples 19 and 20

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 19 and 20 were obtained by the same process as those inExamples 19 and 20 except that 3.0×10⁻⁴ mol/dm³ of a dye (C10) and6.0×10⁻⁴ mol/dm³ of a dye (C3) were used instead of dye (16),respectively.

Comparative Examples 21 and 22

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 21 and 22 were obtained by the same process as those inExamples 21 and 22 except that 3.0×10⁻⁴ mol/dm³ of a dye (C10) and3.0×10⁻⁴ mol/dm³ of a dye (C6) were used instead of dye (4),respectively.

Comparative Examples 23 and 24

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 23 and 24 were obtained by the same process as those inExamples 23 and 24 except that 3.0×10⁻⁴ mol/dm³ of a dye (C10) and3.0×10⁻⁴ mol/dm³ of a dye (C11) were used instead of dye (13),respectively.

Comparative Examples 25 and 26

Working electrodes 11 and dye-sensitized solar cells 100 of ComparativeExamples 25 and 26 were obtained by the same process as those inExamples 25 and 26 except that 3.0×10⁻⁴ mol/dm³ of a dye (C10) and3.0×10⁻⁴ mol/dm³ of a dye (C12) were used instead of dye (17),respectively.

Dyes (C1) to (C12) used in Comparative Examples are shown below.

<Measurement of Energy Conversion Efficiency>

Battery properties of the dye-sensitized solar cells 100 obtained inExamples 1 to 26 and Comparative Examples 1 to 26 were measured by usinga solar simulator under AM-1.5 (1000 W/m²). The results are shown inTables 5 and 6.

It is noted that the energy conversion efficiency (η:%) is a valueobtained by sweeping voltage of the dye-sensitized solar cell 100 usinga source meter and measuring response current, and then, calculating avalue of a maximum output divided by light intensity per 1 cm², themaximum output being the product of the voltage and the current, andmultiplying the calculated value by 100 to represent the value bypercent. That is, the energy conversion efficiency (η:%) is representedby (maximum output/light intensity per 1 cm²)×100.

<Peeling Test>

For evaluating the adsorptive properties (adhesion) of the dye, apeeling test was performed. The results are shown in Tables 5 and 6.

The peeling test was performed by the following procedure. First, foreach of the working electrodes 11, an absorption spectrum of a surfaceof the dye-supported metal oxide layer 14 was measured using a UVspectrometer (measured wavelength was in the range of 350 nm to 950 nm),and initial absorbance at peak wavelength was obtained. Next, theworking electrode 11 was immersed into 100 cm³ of acetonitrile mixturecontaining 10% by weight of water for 2 hours, and then, measurement ofabsorption spectrum was performed by the same manner and absorbance atpeak wavelength after immersed in 10 wt % water-containing acetonitrilefor 2 hours was obtained. Finally, based on the initial absorbance andthe absorbance after immersed in 10 wt % water-containing acetonitrilefor 2 hours at peak wavelength, dye residual rate (%)=(absorbance afterimmersed in 10 wt % water-containing acetonitrile for 2 hours/initialabsorbance)×100 was calculated. It is noted that the series ofmeasurement of absorption spectrum were carried out using UV-3101PCmanufactured by SHIMADZU CORPORATION with 5 nm of slit width.

TABLE 5 Conversion Peeling Dye Metal oxide layer efficiency test Example1 Dye (1) ZnO 2.63 22% Example 2 TiO₂ 1.55 25% Example 3 Dye (5) ZnO3.22 90% Example 4 TiO₂ 1.97 83% Example 5 Dye (8) ZnO 1.75 26% Example6 TiO₂ 1.35 23% Example 7 Dye (3) ZnO 2.75 90% Example 8 TiO₂ 1.77 91%Example 9 Dye (9) ZnO 3.52 90% Example 10 TiO₂ 2.11 88% Example 11 Dye(10) ZnO 3.84 89% Example 12 TiO₂ 1.94 84% Comparative Dye (C1) ZnO 1.1418% Example 1 Dye (C2) Comparative TiO₂ 0.97 13% Example 2 ComparativeDye (C3) ZnO 1.37 80% Example 3 Dye (C4) Comparative TiO₂ 1.05 73%Example 4 Comparative Dye (C3) ZnO 1.25 15% Example 5 Dye (C2)Comparative TiO₂ 1.11 17% Example 6 Comparative Dye (C5) ZnO 1.15 65%Example 7 Comparative TiO₂ 1.01 67% Example 8 Comparative Dye (C6) ZnO1.31 83% Example 9 Dye (C4) Comparative TiO₂ 1.23 85% Example 10Comparative Dye (C8) ZnO 1.32 82% Example 11 Dye (C4) Comparative TiO₂1.00 80% Example 12

Table 5 reveals that the dye-sensitized solar cells 100 of Examples 1and 2 have higher energy conversion efficiencies and higher dye residualrates than the dye-sensitized solar cells 100 of Comparative Examples 1and 2. This indicates that, in the case of simply mixing the two typesof dyes, adsorption sites of the metal oxide (sites to which the dye canbe adsorbed) are shared between the 2 types of dyes, which results indecreased adsorption amounts. Moreover, it is indicated that balancecontrol of the adsorption amounts are significantly difficult becausethe two types of dyes have different adsorption strengths, andtherefore, a high conversion efficiency cannot be obtained. Furthermore,it is indicated that the dyes cannot withstand the peeling test becausethe dyes each have only one carboxylic acid.

Table 5 reveals that the dye-sensitized solar cells 100 of Examples 3and 4 have higher energy conversion efficiencies and higher dye residualrates than the dye-sensitized solar cells 100 of Comparative Examples 3and 4. This indicates that the dyes cannot withstand the peeling testbecause one dye has only one carboxylic acid and therefore is veryliable to be peeled off.

Table 5 reveals that the dye-sensitized solar cells 100 of Examples 5and 6 have higher energy conversion efficiencies and higher dye residualrates than the dye-sensitized solar cells 100 of Comparative Examples 5and 6.

Table 5 reveals that the dye-sensitized solar cells 100 of Examples 7and 8 have higher energy conversion efficiencies and higher dye residualrates than the dye-sensitized solar cells 100 of Comparative Examples 7and 8. This indicates that, in the case of using dye (C5) in which amethyl group is introduced instead of the yellow unit A, high values canbe obtained neither in the conversion efficiency measurement nor in thepeeling test.

Table 5 reveals that the dye-sensitized solar cells 100 of Examples 9and 10 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 9 and 10.

Table 5 reveals that the dye-sensitized solar cells 100 of Examples 11and 12 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 11 and 12.

TABLE 6 Metal oxide Conversion Dye layer efficiency Peeling test Example13 Dye (2) ZnO 1.65 23% Example 14 TiO₂ 1.52 27% Example 15 Dye (6) ZnO1.79 71% Example 16 TiO₂ 1.51 65% Example 17 Dye (14) ZnO 1.67 77%Example 18 TiO₂ 1.49 72% Example 19 Dye (16) ZnO 1.55 66% Example 20TiO₂ 1.55 66% Example 21 Dye (4) ZnO 1.79 90% Example 22 TiO₂ 1.58 83%Example 23 Dye (13) ZnO 1.58 89% Example 24 TiO₂ 1.51 85% Example 25 Dye(17) ZnO 1.61 33% Example 26 TiO₂ 1.52 31% Comparative Dye (C1) ZnO 0.5655% Example 13 Dye (C8) Comparative TiO₂ 0.33 60% Example 14 ComparativeDye (C9) ZnO 0.30 39% Example 15 Comparative TiO₂ 0.28 33% Example 16Comparative Dye (C10) ZnO 0.37 68% Example 17 Comparative TiO₂ 0.31 58%Example 18 Comparative Dye (C10) ZnO 0.45 61% Example 19 Dye (C3)Comparative TiO₂ 0.40 52% Example 20 Comparative Dye (C10) ZnO 0.61 59%Example 21 Dye (C6) Comparative TiO₂ 0.34 53% Example 22 Comparative Dye(C10) ZnO 0.51 51% Example 23 Dye (C11) Comparative TiO₂ 0.27 44%Example 24 Comparative Dye (C10) ZnO 0.47 52% Example 25 Dye (C12)Comparative TiO₂ 0.25 49% Example 26

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 13and 14 have higher energy conversion efficiencies than thedye-sensitized solar cells 100 of Comparative Examples 13 and 14.Especially, it is confirmed that the dye-sensitized solar cells 100 ofComparative Examples 13 and 14 have extremely low photoelectricconversion efficiencies and have little practicability.

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 15and 16 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 15 and 16. On the other hand, in the case of using dye (C9) inwhich a methyl group is introduced instead of the yellow unit A, highvalues can be obtained neither in the conversion efficiency measurementnor in the peeling test. Especially, it is confirmed that thedye-sensitized solar cells 100 of Comparative Examples 15 and 16 haveextremely low photoelectric conversion efficiencies and have littlepracticability.

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 17and 18 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 17 and 18. On the other hand, in the case of using dye (C10)not including an amide bond as a linking group, a high conversionefficiency cannot be obtained. Especially, it is confirmed that thedye-sensitized solar cells 100 of Comparative Examples 17 and 18 haveextremely low photoelectric conversion efficiencies and have littlepracticability.

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 19and 20 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 19 and 20.

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 21and 22 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 21 and 22.

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 23and 24 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 23 and 24.

Table 6 reveals that the dye-sensitized solar cells 100 of Examples 25and 26 have higher energy conversion efficiencies and higher dyeresidual rates than the dye-sensitized solar cells 100 of ComparativeExamples 25 and 26.

Moreover, the above results reveal that the (combined) dyes used inExamples 1 to 26, in which a structure having a maximum absorptionwavelength λmax of 350 to 500 nm in a methanol solution and a cyanineskeleton having a maximum absorption wavelength λmax of 500 to 700 nm ina methanol solution are bonded via a linking group, have higher dyeresidual rates and are excellent in energy conversion efficiency incomparison with the cases of using the (uncombined) dyes in combination.These facts indicates that, in the case of the (combined) dye havingsuch structure, adsorption to the surface of the metal oxide ispromoted, and/or, the adsorption condition of the dye is such that thedye is hard to peel off, which results from steric hindrance of the dyestructure, and also indicates that electron injection properties to themetal oxide (semiconductor material) are improved.

Furthermore, the above results reveal that the (combined) dye havingsuch structure exhibit comparable dye residual rate but significantlyexcellent energy conversion efficiency in the case of the dye-sensitizedsolar cell 100 having the metal oxide layer 13 substantially composed ofzinc oxide in comparison with the case of the dye-sensitized solar cell100 having the metal oxide layer 13 substantially composed of titaniumoxide.

<Measurement of Ultraviolet-Visible Absorption Spectrum>

An Ultraviolet-visible absorption spectrum was measured for dye (5), dye(C3), dye (C4), and a mixture of dye (C3) and dye (C4) at a ratio of1:1. The measurement was performed by using a UV spectrometer (U-3010)manufactured by Hitachi, Ltd., and using a sample prepared by addingeach of the dyes to methanol (CH₃OH; solvent) so that the absorbance isin the range of 0.5 to 1.0. The results are shown in FIGS. 3 to 6.

It should be noted that the present invention is in no way limited tothe above described embodiments and Examples, but various modificationsmay be arbitrarily made within the spirit of the present invention, asdescribed above.

INDUSTRIAL APPLICABILITY

As described above, the present invention can be widely and effectivelyutilized in electronic and electric materials associated withphotoelectric conversion devices such as dye-sensitized solar cells;electronic and electric devices; and equipment, facilities, systems, andthe like provided with the materials or the devices.

REFERENCE SIGNS LIST

11 . . . working electrode, 12 . . . substrate, 12 a . . . conductivesurface, 13 . . . metal oxide layer, 14 . . . dye-supported metal oxideelectrode, 21 . . . counter electrode, 22 a . . . conductive surface, 22. . . substrate, 31 . . . electrolyte, 41 . . . spacer, 100 . . .photoelectric conversion device.

The invention claimed is:
 1. A photoelectric conversion device dye, thedye being a compound of the structure represented by the followinggeneral formula (I):

wherein: A is selected from the group consisting of the followingformulas (IV) to (VII):

wherein: S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; q is 0 or 1, and thesubstituent —Y¹—COOH substitutes S¹;

wherein: S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; R²⁴ is a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or ananchor group; u is 0 or 1; and the substituent —Y¹—COOH substitutes S²and/or S³:

wherein: R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group; R²⁷is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an arylgroup having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30carbon atoms, or an anchor group; R²⁸ to R³¹ are each independently ahydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbonatoms, or an aryl group having 6 to 12 carbon atoms, where R²⁸ and R³⁰may each be eliminated to form an unsaturated bond, or R²⁹ and R³¹ maybe linked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein: R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms; and R³⁴ to R⁴¹ are each independently a hydrogen atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an alkylgroup having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbonatoms, or an arylalkyl group having 7 to 30 carbon atoms, B comprises acyanine skeleton having a maximum absorption wavelength λmax of 500 to700 nm in a methanol solution; Z¹ is any one divalent linking groupselected from —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or anarylalkyl group having 7 to 20 carbon atoms; Y¹ and Y² are eachindependently an alkylene group having 1 to 8 carbon atoms, or a singlebond; r is 1 or 2; m and n are each independently an integer of 0 to 2;and (m+n) is 1 or more.
 2. The photoelectric conversion device dyeaccording to claim 1, wherein the dye is a compound of the structurerepresented by the following general formula (II):

wherein: X¹ and X² are each independently an oxygen atom, a sulfur atom,a selenium atom, CR³R⁴, or NR⁵; R¹ to R⁵ are each independently ahydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenylgroup having 2 to 8 carbon atoms, or an alkynyl group having 2 to 8carbon atoms, where R¹ to R⁵ may each be independently substituted by ahalogen atom, a nitro group, a cyano group, an amino group, a hydroxylgroup, an ether group, a carbonyl group, an aromatic ring, aheterocyclic ring, or a metallocenyl group, and R³ and R⁴ may be linkedto form an alicyclic group having a 3- to 6-membered ring; R⁶ to R⁸ areeach independently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, an aryl group having 6 to 12 carbon atoms, a halogen atom, or acyano group; R⁹ to R¹⁶ are each independently a hydrogen atom, a halogenatom, an alkyl group having 1 to 20 carbon atoms, or an aryl grouphaving 6 to 12 carbon atoms; in R⁹ to R¹⁶, R⁹ and R¹¹ may be eliminatedor R¹³ and R¹⁵ may be eliminated to each form an unsaturated bond, orR¹⁰ and R¹² may be linked or R¹⁴ and R¹⁶ may be linked to each form abenzene ring which may have a substituent, a naphthalene ring which mayhave a substituent, or a phenanthrene ring which may have a substituent;p is 1 or 2; Z¹ in the formula replaces R¹ to R¹⁶ or a hydrogen atomcontained in R¹ to R¹⁶; a substituent —Y²—COOH in the formula replacesR¹ to R¹⁶ or a hydrogen atom contained in R¹ to R¹⁶; An^(b−) is ab-valent anion; a is 1 or 2, and is a coefficient for keeping a chargeof the entire dye neutral; b is 1 or 2; and m, n, r, Z¹, A, Y¹, and Y²are the same as described in the general formula (I).
 3. Thephotoelectric conversion device dye according to claim 2, wherein thedye is a compound of the structure represented by the following generalformula (III):

wherein: D¹ and D² are each independently a benzene ring which may havea substituent, a naphthalene ring which may have a substituent, or aphenanthrene ring which may have a substituent; two substituents—Y²—COOH in the formula each replace R¹ to R⁸ or a hydrogen atomcontained in R¹ to R⁸, or substitute the benzene ring, the naphthalenering, or the phenanthrene ring represented by D¹ and D²; and the othervariables are the same as described in formula (II).
 4. A compound ofthe structure represented by the following formula (IX):

wherein: A is selected from the group consisting of the followingformulas (IV) to (VII):

wherein: S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; q is 0 or 1, and thesubstituent —Y¹—COOH substitutes S¹;

wherein: S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; R²⁴ is a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or ananchor group; u is 0 or 1; and the substituent —Y¹—COOH substitutes S²and/or S³:

wherein: R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group; R²⁷is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an arylgroup having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30carbon atoms, or an anchor group; R²⁸ to R³¹ are each independently ahydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbonatoms, or an aryl group having 6 to 12 carbon atoms, where R²⁸ and R³⁰may each be eliminated to form an unsaturated bond, or R²⁹ and R³¹ maybe linked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein: R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms; and R³⁴ to R⁴¹ are each independently a hydrogen atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an alkylgroup having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbonatoms, or an arylalkyl group having 7 to 30 carbon atoms; Z¹ is any onedivalent linking group selected from —CONR—, —NRCO—, —SO₂NR—, and—NRSO₂—; R in Z¹ is a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, or an arylalkyl group having 7 to 20 carbon atoms; D¹ is abenzene ring which may have a substituent, a naphthalene ring which mayhave a substituent, or a phenanthrene ring which may have a substituent;R¹ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, analkenyl group having 2 to 8 carbon atoms, or an alkynyl group having 2to 8 carbon atoms, each of which may be substituted by a halogen atom, anitro group, a cyano group, an amino group, a hydroxyl group, an ethergroup, a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group; R⁴² are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbonatoms, a halogen atom, or a cyano group; X¹ is an oxygen atom, a sulfuratom, a selenium atom, CR³R⁴, or NR⁵; R³ to R⁵ are each independently ahydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenylgroup having 2 to 8 carbon atoms, or an alkynyl group having 2 to 8carbon atoms; R³ to R⁵ may each be independently substituted by ahalogen atom, a nitro group, a cyano group, an amino group, a hydroxylgroup, an ether group, a carbonyl group, an aromatic ring, aheterocyclic ring, or a metallocenyl group, and R³ and R⁴ may be linkedto form an alicyclic group having a 3- to 6-membered ring; Y¹ is analkylene group having 1 to 8 carbon atoms, or a single bond; m is 0 to2; An^(b−) is a b-valent anion; a is 1 or 2, and is a coefficient forkeeping a charge of the entire dye neutral; and b is 1 or
 2. 5. Thecompound according to claim 4, wherein the dye is a compound of thestructure represented by the following formula (X):

wherein: A is selected from the group consisting of the followingformulas (IV) to (VII):

wherein: S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; q is 0 or 1, and thesubstituent —Y¹—COOH substitutes S¹;

wherein: S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; R²⁴ is a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or ananchor group; u is 0 or 1; and the substituent —Y¹—COOH substitutes S²and/or S³:

wherein: R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group; R²⁷is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an arylgroup having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30carbon atoms, or an anchor group; R²⁸ to R³¹ are each independently ahydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbonatoms, or an aryl group having 6 to 12 carbon atoms, where R²⁸ and R³⁰may each be eliminated to form an unsaturated bond, or R²⁹ and R³¹ maybe linked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein: R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms; and R³⁴ to R⁴¹ are each independently a hydrogen atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an alkylgroup having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbonatoms, or an arylalkyl group having 7 to 30 carbon atoms; Z² is any onedivalent linking group selected from —CONR—, —NRCO, —SO₂NR—, and—NRSO₂—, R in Z² is a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, or an arylalkyl group having 7 to 20 carbon atoms; D¹ is abenzene ring which may have a substituent, a naphthalene ring which mayhave a substituent, or a phenanthrene ring which may have a substituent;R¹ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, analkenyl group having 2 to 8 carbon atoms, or an alkynyl group having 2to 8 carbon atoms, each of which may be substituted by a halogen atom, anitro group, a cyano group, an amino group, a hydroxyl group, an ethergroup, a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group, X¹ is an oxygen atom, a sulfur atom, a seleniumatom, CR³R⁴, or NR⁵; R³ to R⁵ are each independently a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 8carbon atoms, or an alkynyl group having 2 to 8 carbon atoms, where R³to R⁵ may each be independently substituted by a halogen atom, a nitrogroup, a cyano group, an amino group, a hydroxyl group, an ether group,a carbonyl group, an aromatic ring, a heterocyclic ring, or ametallocenyl group, and R³ and R⁴ may be linked to form an alicyclicgroup having a 3- to 6-membered ring; An^(b−) is a b-valent anion; a is1 or 2, and is a coefficient for keeping the charge of the entire dyeneutral; and b is 1 or
 2. 6. A photoelectric conversion devicecomprising a working electrode comprising a dye supported on a metaloxide layer, the dye being a compound of the structure represented bythe following general formula (I):

wherein: A is selected from the group consisting of the followingformulas (IV) to (VII):

wherein: S¹ is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; R¹⁷ to R²⁰ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; q is 0 or 1, and thesubstituent —Y¹—COOH substitutes S¹;

wherein: S² is an aromatic ring which may have a substituent, or aheterocyclic ring which may have a substituent; S³ is a sulfur atom or astructure represented by the following formula (Va); R²¹ to R²³ are eachindependently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, a halogen atom, or a cyano group; R²⁴ is a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or ananchor group; u is 0 or 1; and the substituent —Y¹—COOH substitutes S²and/or S³:

wherein: R²⁵ to R²⁶ are each independently a hydrogen atom, an alkylgroup having 1 to 8 carbon atoms, a halogen atom, or a cyano group; R²⁷is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an arylgroup having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30carbon atoms, or an anchor group; R²⁸ to R³¹ are each independently ahydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbonatoms, or an aryl group having 6 to 12 carbon atoms, where R²⁸ and R³⁹may each be eliminated to form an unsaturated bond, or R²⁹ and R³¹ maybe linked to form a benzene ring which may have a substituent, anaphthalene ring which may have a substituent, or a phenanthrene ringwhich may have a substituent; t is 0 or 1; and the substituent —Y¹—COOHsubstitutes S³; and

wherein: R³² to R³³ are each independently a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms, or an arylalkyl group having 7 to 30carbon atoms; and R³⁴ to R⁴¹ are each independently a hydrogen atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an alkylgroup having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbonatoms, or an arylalkyl group having 7 to 30 carbon atoms; B comprises acyanine skeleton having a maximum absorption wavelength λmax of 500 to700 nm in a methanol solution; Z¹ is a divalent linking group selectedfrom —CONR—, —NRCO—, —SO₂NR—, and —NRSO₂—; R in Z¹ is a hydrogen atom,an alkyl group having 1 to 8 carbon atoms, or an arylalkyl group having7 to 20 carbon atoms; Y¹ and Y² are each independently an alkylene grouphaving 1 to 8 carbon atoms, or a single bond; r is 1 or 2; m and n areeach independently an integer of 0 to 2; and (m+n) is 1 or more.
 7. Thephotoelectric conversion device according to claim 6, wherein the dye isa compound of the structure represented by the following general formula(II):

wherein: X¹ and X² are each independently an oxygen atom, a sulfur atom,a selenium atom, CR³R⁴, or NR⁵; R¹ to R⁵ are each independently ahydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenylgroup having 2 to 8 carbon atoms, or an alkynyl group having 2 to 8carbon atoms, where R¹ to R⁵ may each be independently substituted by ahalogen atom, a nitro group, a cyano group, an amino group, a hydroxylgroup, an ether group, a carbonyl group, an aromatic ring, aheterocyclic ring, or a metallocenyl group, and R³ and R⁴ may be linkedto form an alicyclic group having a 3- to 6-membered ring; R⁶ to R⁸ areeach independently a hydrogen atom, an alkyl group having 1 to 8 carbonatoms, an aryl group having 6 to 12 carbon atoms, a halogen atom, or acyano group; R⁹ to R¹⁶ are each independently a hydrogen atom, a halogenatom, an alkyl group having 1 to 20 carbon atoms, or an aryl grouphaving 6 to 12 carbon atoms; in R⁹ to R¹⁶, R⁹ and R¹¹ may be eliminatedor R¹³ and R¹⁵ may be eliminated to each form an unsaturated bond, orR¹⁰ and R¹² may be linked or R¹⁴ and R¹⁶ may be linked to each form abenzene ring which may have a substituent, a naphthalene ring which mayhave a substituent, or a phenanthrene ring which may have a substituent;p is 1 or 2; Z¹ in the formula replaces R¹ to R¹⁶ or a hydrogen atomcontained in R¹ to R¹⁶; the substituent —Y²—COOH in the formula replacesR¹ to R¹⁶ or a hydrogen atom contained in R¹ to R¹⁶; An^(b−) is ab-valent anion; a is 1 or 2, and is a coefficient for keeping a chargeof the entire dye neutral; b is 1 or 2; and m, n, r, Z¹, A, Y¹, and Y²are the same as described in formula (I).
 8. The photoelectricconversion device according to claim 7, wherein the dye is a compound ofthe structure represented by the following general formula (III):

wherein: D¹ and D² are each independently a benzene ring which may havea substituent, a naphthalene ring which may have a substituent, or aphenanthrene ring which may have a substituent; two substituents—Y²—COOH in the formula each replace R¹ to R⁸ or a hydrogen atomcontained in R¹ to R⁸, or substitute the benzene ring, the naphthalenering, or the phenanthrene ring represented by D¹ and D²; and the othervariables are the same as described in formula (II).